diff --git a/src/storage/caas.js b/src/storage/caas.js
index cda1bd88d..d1cd8ff0b 100644
--- a/src/storage/caas.js
+++ b/src/storage/caas.js
@@ -58,7 +58,7 @@ function getBoxBackupDetails(apiConfig, id, callback) {
         var region = apiConfig.region || 'us-east-1';
 
         var details = {
-            backupScriptArguments: [ 's3', s3Url, result.accessKeyId, result.secretAccessKey, region, apiConfig.key, result.sessionToken ]
+            backupScriptArguments: [ 's3', s3Url, result.accessKeyId, result.secretAccessKey, region, '', apiConfig.key, result.sessionToken ]
         };
 
         callback(null, details);
@@ -80,7 +80,7 @@ function getAppBackupDetails(apiConfig, appId, dataId, configId, callback) {
         var region = apiConfig.region || 'us-east-1';
 
         var details = {
-            backupScriptArguments: [ 's3', appId, s3ConfigUrl, s3DataUrl, result.accessKeyId, result.secretAccessKey, region, apiConfig.key, result.sessionToken ]
+            backupScriptArguments: [ 's3', appId, s3ConfigUrl, s3DataUrl, result.accessKeyId, result.secretAccessKey, region, '', apiConfig.key, result.sessionToken ]
         };
 
         callback(null, details);