How to conditionally compile VC6 resources

Question

Hi,

depending on a compile switch (values are COMPILE_A or COMPILE_B), which is set in the form of an envorinment variable, I want to compile my application with different settings, like application name and splash screen.

I got this far:

1. In "Project / Settings / C/C++ / Preprocessor Definitions" I added $(COMPILESWITCH) (results in command line option /D "$(COMPILESWITCH)").

2. In stdafx.h I can use the following code, which means I correctly defined the preprocessor definition via the command line parameter:

    #if defined COMPILE_A
    #   define IDB_SPLASH IDB_SPLASH_A
    # elif defined COMPILE_B
    #   define IDB_SPLASH IDB_SPLASH_B
    # else
    #   error Unknown or undefined target compile switch; cannot compile!
    # endif

But I've noticed the "Condition" property under "ResourceView / [right-click] / Properties"... The help text says this:

Condition

Determines the inclusion of the resource. For example, if the condition is _DEBUG, this resource would be included only in debug builds.

This looks like the elegant way of doing it, right?

Specifiying _DEBUG as condition works. So as _DEBUG is specified via /D _DEBUG my $(COMPILESWITCH) should also work, right?
For some reason it doesn't; why?

Or is there even another, better way to achieve what I want?