[I hope I'm not double posting...]
Actually, I was bored and browsing the CVS...
looks like the installer on there (Install\k-meleon.nsi) sets it. However, it also references K-Meleon 0.45... I guess that's kinda old. I wonder what the current installer looks like, since it's probably possible to make that do things for us.
Alternatively, if we _really_ want to (I'm actually kinda against this), I suppose it would be possible to have the macros plugin support registry writes
That's going kinda bloated though, even if it does simply move the registry stuff from somewhere else that would use it anyway.