[CMake] CPack RPM: why not <name>-<version>-<release>-<arch>.rpm filename?

[Winfried Dobbe]

When I build a RPM with current CVS CMAKE/CPack for project  
<projectname>
the file name of the generated rpm is:
<projectname>-<version>-Linux.rpm

The common filename for an rpm is
<projectname>-<version>-<release>-<architecture>.rpm

Putting "Linux" in the file name doesn't provide much information  
because
I don't know any other OS that uses the RPM package system.

When I look in the CPackRPM.cmake module I see that the following line  
is
commented out:

#SET(CPACK_RPM_FILE_NAME
"${CPACK_RPM_PACKAGE_NAME}-${CPACK_RPM_PACKAGE_VERSION}-$ 
{CPACK_RPM_PACKAGE_RELEASE}-${CPACK_RPM_PACKAGE_ARCHITECTURE}.rpm")
and replaced by:
SET(CPACK_RPM_FILE_NAME "${CPACK_OUTPUT_FILE_NAME}")

When I set the following variable in my CMakeLists.txt:
set(CPACK_OUTPUT_FILE_NAME
"${CMAKE_PROJECT_NAME}-${CPACK_PACKAGE_VERSION_MAJOR}.$ 
{CPACK_PACKAGE_VERSION_MINOR}.${CPACK_PACKAGE_VERSION_PATCH}-$ 
{CPACK_RPM_PACKAGE_RELEASE}-${CPACK_RPM_PACKAGE_ARCHITECTURE}.rpm")

the rpm is generated with the filename that I expect in directory
_CPack_Packages/Linux/RPM, but after that I get the error:
CPack Error: Problem copying the package:
/home/wdobbe/checkout/btbuild/_CPack_Packages/Linux/RPM/ 
buildtools-1.0.0-Linux.rpm
to /home/wdobbe/checkout/btbuild/buildtools-1.0.0-Linux.rpm
CPack Error: Error when generating package: buildtools
make: *** [package] Error 1

So even though I set the rpm output file name, CPack still looks for the
"default" file name.

Can somebody (Eric?) clarify this behaviour?

thanks in advance,
Winfried