The following assumes you are using a project (.cbp file)
Note: I don't use RC2 so no idea if this applies to it.
Project -> "Build Options"
On left hand column select the top item, this should be the project name, with that selected change.
"selected Compiler" to your compiler you wish to use.
if it asks did you wish to use this compiler with all your targets click "Yes"
Do a re-build and see if it worked.
Tim S