Calling a stored procedure from C++ using ADO-OraOLEDB

I am calling a stored procedure that takes two parameters
xml_in in varchar and xml_out out varchar

The stored procedure is allways getting a "-1" with trail spaces as the imput parameter.
I use similar code to get the output parameters and that works fine.

The code is written in VC++ 6.0 using ADO with OraOLEDB

Any ideas?

Thanks,

JC.