Registering XPCOM components from XPInstall:

I was wondering if anyone knows how to register a XPCOM dll from a XPInstall
script. There is documentation that indicates that it can be done, but I
have not found a way to actually do it. Simply copying my .dll and .xpt and
registering my chrome is not enough. I still need to run regxpcom externally
to actually register my component.
Thanks for the help.