Did you try it ?
Yes in 2003 and with or without the preprocessor macro defined I only get the original dialog so the copied template never executes and controls added to the copied dialog resource never show up in the list of controls in the "add member variable" dialog. Never used this feature before today so I never saw it work in VC6.
"Just about every question you've asked over the last 3-4 days has been "urgent". Perhaps a little planning would be helpful?"
Colin Angus Mackay in the C# forum