Categories should include X-Red-Hat-Base;Application;System;

namespace the desktop file, redhat-rhn-register.desktop

move to /usr/share/applications

The desktop file labeled "Red Hat Network" should really register if you aren't,
and launch up2date or package tool otherwise, I don't know if this does that.

Comment should not say "Client" but just "Access Red Hat Network" or the like.
"Register" seems unneeded too, just "Access" is fine.