R – Build merge module without Devenv from .vdproj

I read quit a few Stackoverflow Questions about building mergemodules via commandline but all of them were accepted when either somebody suggested to use devenv for compilation or use Dark to create wix-files from existing msi files.

Considering the following:

• VisualStudio isn't installed on the buildserver I have to use.
• I am using nant + msbuild to compile the solutions
• I would like to compile mergemodules from .vdproj (because Visual Studio detects dependencies automatically)
• and create a msi setup from multiple mergemodules

… how can I build the merge modules from commandline without devenv and without loosing the comfort of automated dependencie resolving for mergemodules in visualstudio?
Maybe there is a nanttask for it I haven't found?