refreshing in-memory profile list?

I am working on an application that uses a mozilla based helper program,
and it makes and uses its own profile, so that it can be run at the
same time as a copy of Mozilla.  But I would like to be able to delete
the profile that it is using when it exits.  When I try to do that
with the normal profile manager from 
do_GetService(NS_PROFILE_CONTRACTID), it ends up writing a stale
list of existing profiles to the registry (because other copies of
the helper program have been started and created new profiles).  How
do I get the profile manager to re-load from disk the list of profiles
that exist?

(Given the lack of locks on the registry, this stuff will always be
race-pron, but at least I can try to do the right thing.)

Also, it would be nice if there were a public interface to set the
last used profile, because I don't want the profiles used by my
helper program to be considered the "last used" profile, and right
now I am using a hack to make an nsIRegistry to muck with the
registry myself.

P.S. I am using 1.5 right now, but if a newer version fixed any of this
stuff, I would be happy to switch.
Thanks.

William Bardwell
[email protected]