How to make install rule with a wildcard for files that don't exist?

[Dan Princ]

Is there a way to set up installation to copy all files with a given extension, if these files are generated during build (so they don't exist when qmake is run)?
What I tried is basically this:

csmes.path = $$PATH_INSTALL_BIN
csmes.files = $$OUT_PWD/*.csmes
INSTALLS += csmes

but this doesn't work, the rule generated in a makefile is incorrect. I also tried to use the no_check_exist option, but that only seems to work if the files are explicitly listed, which I'm really trying to avoid.
Is there a way to do this directly in a pro file? I can figure out some workaround and run a custom script during installation, I'm just wondering if there's an easier way. Thanks for any help.