[plt-scheme] faking exception source location

How can I fake the source location when raising an exception? I'm 
working on a macro that may detect errors at expansion time; I want 
DrScheme to highlight the source syntax, not the macro definition, when 
such an error occurs. I know how to use syntax/loc et al to use the 
source syntax location in the target syntax, but I can't figure out how 
to give syntax location information to `raise' or any of the exception 
structures.

Thanks,
Dave