I believe this is what you are looking for...
In Data Sources --> LDMS --> MainDataSet - click the Edit button & go to Query.
There is a section in the query that says:
WHERE (A1.CLIENTCONFIGURATIONNAME LIKE N'%ASI-Client%' AND A2.SERVER = N'No' AND A3.DRIVELETTER = N'C')
delete that section & save. If you still want the Driveletter designation, you can mod it to this:
WHERE (A3.DRIVELETTER = N'C')