I had the same issue; I do not know what Cisco says about it, but I could not get Call Studio to return a result from a stored procedure either. The stored procedure is run; I had no problem using it to update a row, the issue was then trying to return something.
I ended up just restructuring the way I wanted to do things, and only used stored procedures for inserts.
The other option would be to write your own DB element in Java. I plan on doing that to allow for stored procedures at some point, but haven’t yet as I didn’t have a big enough need for it.