64 Bit SSRS And Sybase ASE 15.0 Drivers

Hello everyone,
I'm running into an unusual situation with 64 bit SSRS and Sybase drivers and I'm hoping someone has a similar scenario. This isn't the usual OLE DB/ODBC parameter problem.

Our first issue was that we had 32 bit sybase (12.5) drivers installed on our 64 bit machine and SSRS Report Server could not utilize drivers. We resolved this by installing the 15.0 64 bit drivers (the only Sybase 64 bit drivers we know of).

The real problem is as follows:
In SSRS, we can design reports with parameters. BIDS prevents utilizing named parameters while connecting to a database via ODBC or OLE DB (I'm not sure if this is an ODBC standard or if it was just coded this way to avoid problems). Prior to our new server (and new 64 bit drivers) we were always able to use unnamed parameters. We were able to get all of our reports to work with the question mark syntax.

The new 15.0 drivers apparently do not support this same implementation of unnamed parameters (using ? used to work with 12.5 drivers but now we get an error).
[---> System.Data.Odbc.OdbcException: ERROR [ZZZZZ] [Sybase][ODBC Driver][Adaptive Server Enterprise]There is no host variable corresponding to the one specified by the PARAM datastream. This means that this variable '@dr_t_a0' was not used in the preceding DECLARE CURSOR or SQL command.]

If I open the RDL file and change the ? to @VariableName and upload to server, it appears that the 15.0 drivers do support named parameters.

1) Is there a specific reason BIDS prevents the named parameters from being used?
2) Has anyone seen this behavior change with Reporting Services and the upgraded Sybase drivers?
3) Does anyone have any advice on things I can try?

I realize that this may be a question better directed towards sybase, and I am currently working on having our DBAs open up a support case to see if they have any history of someone working with SSRS and Sybase 15.0 drivers.

Thank you!

Regards,

Dan