Locate merge module with a Build variable

The Merge Module Properties window allows to choose the fully qualified file name for a merge module to include in the project.
I just miss the possibility to use a Build Variable so that porting the .msifact file to another machine would be easier.
Build Variables can be used nearly every where else to specify a source directory. Why not to specify merge modules ?
Can I hope seeing this in a future version ?

Philippe ALLAIN