diff --git a/lib/device.js b/lib/device.js
index 0e0904e..d70a7f9 100644
--- a/lib/device.js
+++ b/lib/device.js
@@ -51,6 +51,8 @@ function sanitizeParameterValue(parameterValue) {
         }
         break;
       case 'xsd:string':
+      case 'xsd:base64':
+      case 'xsd:hexBinary':
         if (typeof parameterValue[0] !== 'string') {
           parameterValue[0] = '' + parameterValue[0];
         }
diff --git a/lib/session.coffee b/lib/session.coffee
index b08e306..af38b4e 100644
--- a/lib/session.coffee
+++ b/lib/session.coffee
@@ -447,7 +447,7 @@ runVirtualParameters = (sessionContext, provisions, startRevision, endRevision,
                 _returnValue.value[1] = 'xsd:string'
 
             if not _returnValue.value[0]? or
-                _returnValue.value[1] not in ['xsd:int', 'xsd:unsignedInt', 'xsd:boolean', 'xsd:string', 'xsd:dateTime']
+                _returnValue.value[1] not in ['xsd:int', 'xsd:unsignedInt', 'xsd:boolean', 'xsd:string', 'xsd:dateTime', 'xsd:base64', 'xsd:hexBinary']
               if counter & 1
                 callback(null, {code: 'script', message: 'Invalid virtual parameter value attribute'})
               return counter = 0