When opening the Settings Manager in Xfce 4.4.2 on Xubuntu 8.10, the two buttons whose strings are in xfce4-session's translation to en (GB) still include the "Button Label|" part. I've checked the translations, but they're done in exactly the same way as they are in mcs_manager, so I'm not sure what the problem is. See also https://bugs.launchpad.net/ubuntu/+source/xfce-mcs-manager/+bug/313688
This is a Xubuntu-specific issue, please mark this bug as invalid, thanks.
Marked as invalid per request.