QMAKE_EXTRA_COMPILERS and VC 2005

When using QMAKE_EXTRA_COMPILERS for a custom file type as follows:

vnVersion.commands = $(PYDIR)/python ../../../WZrtas/Tools/svnrev/svnrev.py
../../ ${QMAKE_FILE_IN} ../../build/${QMAKE_FILE_BASE}.h
svnVersion.output = ../../build/${QMAKE_FILE_BASE}.h
svnVersion.input = VERSION_TEMPLATES
svnVersion.variable_out = HEADERS

QMAKE_EXTRA_COMPILERS += svnVersion

VERSION_TEMPLATES += ./Killerversion.svn

then it works perfect using a makefile, but when using qmake to create a vc2005 vcproj out of the pro file, the Killerversion.svn is nowhere to be found in the project, though the Killerversion.h is added but with no custom build step