diff --git a/src/backups.js b/src/backups.js
index 51194fe14..4ac72d00c 100644
--- a/src/backups.js
+++ b/src/backups.js
@@ -114,32 +114,6 @@ function getByAppIdPaged(page, perPage, appId, callback) {
     });
 }
 
-function getBoxBackupCredentials(appBackupIds, callback) {
-    assert(util.isArray(appBackupIds));
-    assert.strictEqual(typeof callback, 'function');
-
-    var now = new Date();
-    var filebase = util.format('backup_%s-v%s', now.toISOString(), config.version());
-    var filename = filebase + '.tar.gz';
-
-    settings.getBackupConfig(function (error, backupConfig) {
-        if (error) return callback(new BackupsError(BackupsError.INTERNAL_ERROR, error));
-
-        api(backupConfig.provider).getBackupCredentials(backupConfig, function (error, result) {
-            if (error) return callback(error);
-
-            result.provider = backupConfig.provider;
-            result.id = filename;
-            result.s3Url = 's3://' + backupConfig.bucket + '/' + backupConfig.prefix + '/' + filename;
-            result.backupKey = backupConfig.key;
-
-            debug('getBoxBackupCredentials: %j', result);
-
-            callback(null, result);
-        });
-    });
-}
-
 function getAppBackupCredentials(app, manifest, callback) {
     assert.strictEqual(typeof app, 'object');
     assert(manifest && typeof manifest === 'object');
@@ -252,31 +226,30 @@ function copyLastBackup(app, manifest, callback) {
 function backupBoxWithAppBackupIds(appBackupIds, callback) {
     assert(util.isArray(appBackupIds));
 
-    getBoxBackupCredentials(appBackupIds, function (error, result) {
-        if (error && error.reason === BackupsError.EXTERNAL_ERROR) return callback(new BackupsError(BackupsError.EXTERNAL_ERROR, error.message));
+    var now = new Date();
+    var filebase = util.format('backup_%s-v%s', now.toISOString(), config.version());
+    var filename = filebase + '.tar.gz';
+
+    settings.getBackupConfig(function (error, backupConfig) {
         if (error) return callback(new BackupsError(BackupsError.INTERNAL_ERROR, error));
 
-        debug('backupBoxWithAppBackupIds:  %j', result);
+        api(backupConfig.provider).getBackupDetails(backupConfig, filename, function (error, result) {
+            if (error) return callback(error);
 
-        var args;
-        if (result.provider === 'filesystem') {
-            args = [ 'filesystem', '/tmp/backups', result.id, result.backupKey ];
-        } else {
-            args = [ 's3', result.s3Url, result.accessKeyId, result.secretAccessKey, result.region, result.backupKey ];
-            if (result.sessionToken) args.push(result.sessionToken);
-        }
+            debug('backupBoxWithAppBackupIds: backup details %j', result);
 
-        shell.sudo('backupBox', [ BACKUP_BOX_CMD ].concat(args), function (error) {
-            if (error) return callback(new BackupsError(BackupsError.INTERNAL_ERROR, error));
-
-            debug('backupBoxWithAppBackupIds: success');
-
-            backupdb.add({ id: result.id, version: config.version(), type: backupdb.BACKUP_TYPE_BOX, dependsOn: appBackupIds }, function (error) {
+            shell.sudo('backupBox', [ BACKUP_BOX_CMD ].concat(result.backupScriptArguments), function (error) {
                 if (error) return callback(new BackupsError(BackupsError.INTERNAL_ERROR, error));
 
-                webhooks.backupDone(result.id, null /* app */, appBackupIds, function (error) {
-                    if (error) return callback(error);
-                    callback(null, result.id);
+                debug('backupBoxWithAppBackupIds: success');
+
+                backupdb.add({ id: result.id, version: config.version(), type: backupdb.BACKUP_TYPE_BOX, dependsOn: appBackupIds }, function (error) {
+                    if (error) return callback(new BackupsError(BackupsError.INTERNAL_ERROR, error));
+
+                    webhooks.backupDone(result.id, null /* app */, appBackupIds, function (error) {
+                        if (error) return callback(error);
+                        callback(null, result.id);
+                    });
                 });
             });
         });
diff --git a/src/storage/caas.js b/src/storage/caas.js
index 490eb0d6e..c211059b8 100644
--- a/src/storage/caas.js
+++ b/src/storage/caas.js
@@ -5,7 +5,7 @@ exports = module.exports = {
 
     copyObject: copyObject,
 
-    getBackupCredentials: getBackupCredentials,
+    getBackupDetails: getBackupDetails,
 
     getAllPaged: getAllPaged
 };
@@ -28,6 +28,7 @@ function getBackupCredentials(apiConfig, callback) {
         if (!result.body || !result.body.credentials) return callback(new Error('Unexpected response'));
 
         var credentials = {
+            signatureVersion: 'v4',
             accessKeyId: result.body.credentials.AccessKeyId,
             secretAccessKey: result.body.credentials.SecretAccessKey,
             sessionToken: result.body.credentials.SessionToken,
@@ -40,6 +41,25 @@ function getBackupCredentials(apiConfig, callback) {
     });
 }
 
+function getBackupDetails(apiConfig, id, callback) {
+    assert.strictEqual(typeof apiConfig, 'object');
+    assert.strictEqual(typeof id, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    getBackupCredentials(apiConfig, function (error, result) {
+        if (error) return callback(error);
+
+        var s3Url = 's3://' + apiConfig.bucket + '/' + apiConfig.prefix + '/' + id;
+        var region = apiConfig.region || 'us-east-1';
+
+        var details = {
+            backupScriptArguments: [ 's3', s3Url, apiConfig.accessKeyId, apiConfig.secretAccessKey, region, apiConfig.key, result.sessionToken ]
+        };
+
+        callback(null, details);
+    });
+}
+
 function getAllPaged(apiConfig, page, perPage, callback) {
     assert.strictEqual(typeof apiConfig, 'object');
     assert.strictEqual(typeof page, 'number');
diff --git a/src/storage/filesystem.js b/src/storage/filesystem.js
index 0e86bc582..e518e081b 100644
--- a/src/storage/filesystem.js
+++ b/src/storage/filesystem.js
@@ -6,16 +6,23 @@ exports = module.exports = {
     copyObject: copyObject,
     getAllPaged: getAllPaged,
 
-    getBackupCredentials: getBackupCredentials
+    getBackupDetails: getBackupDetails
 };
 
 var assert = require('assert');
 
-function getBackupCredentials(apiConfig, callback) {
+function getBackupDetails(apiConfig, id, callback) {
     assert.strictEqual(typeof apiConfig, 'object');
+    assert.strictEqual(typeof id, 'string');
     assert.strictEqual(typeof callback, 'function');
 
-    callback(null, {});
+    var backupFolder = apiConfig.backupFolder || '/tmp/backups';
+
+    var details = {
+        backupScriptArguments: [ 'filesystem', backupFolder, id, apiConfig.key ]
+    };
+
+    callback(null, details);
 }
 
 function getAllPaged(apiConfig, page, perPage, callback) {
diff --git a/src/storage/s3.js b/src/storage/s3.js
index a68fc7f6c..98e0326c3 100644
--- a/src/storage/s3.js
+++ b/src/storage/s3.js
@@ -6,7 +6,7 @@ exports = module.exports = {
     copyObject: copyObject,
     getAllPaged: getAllPaged,
 
-    getBackupCredentials: getBackupCredentials
+    getBackupDetails: getBackupDetails
 };
 
 var assert = require('assert'),
@@ -30,6 +30,21 @@ function getBackupCredentials(apiConfig, callback) {
     callback(null, credentials);
 }
 
+function getBackupDetails(apiConfig, id, callback) {
+    assert.strictEqual(typeof apiConfig, 'object');
+    assert.strictEqual(typeof id, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    var s3Url = 's3://' + apiConfig.bucket + '/' + apiConfig.prefix + '/' + id;
+    var region = apiConfig.region || 'us-east-1';
+
+    var details = {
+        backupScriptArguments: [ 's3', s3Url, apiConfig.accessKeyId, apiConfig.secretAccessKey, region, apiConfig.key ]
+    };
+
+    callback(null, details);
+}
+
 function getAllPaged(apiConfig, page, perPage, callback) {
     assert.strictEqual(typeof apiConfig, 'object');
     assert.strictEqual(typeof page, 'number');