Entering arguments into a data environment at runtime???

[jax2]

Hello out there,
I am attempting to use a few Data enviroments in my VB project, and after much wrestling, have gotten them to work - when I put the arguments for the stored procedures in myself. Does anyone know how I might enter this data at runtime? I'd like to access it from code along these lines :

DataEnvironment.StoredProcedureArgument = Now()

or whatever, but have no idea how to do so. Many thanks for any assistance....