SLED10: Install Older Package Version

Hi guys, I would like to install an older version of a package (actually it's the Groupwise client) then the one included on the SLED10 DVD. So I created an add-on source with the older RPM and added the add-on to the control file. Naturally now the autoinstall installs the newest version. I can think of some ways to get the older version installed but I really want to do it the proper way (TM). So I will stay away from trying to delete the newer version from the DVD package database or the like. Now, what is the proper way? ;-)) Thanks in advance, Goetz