[horde] Master User / Ingo only

[Rick Romero]

Hey guys,

I'm interested in possibly doing two things.  First I'm interested in how
a dovecot 'master user' scenario would work.  A master user style login,
by default, would appear like so:
user at domain.com*admin at domain.com

I assume I would use a postauthenticate hook (in IMP where my
authentication occurs) to split the string ($userId), so when logging in to
manage 'user at domain.com', the admin would also get the preferences for
'user at domain.com' from SQL instead of 'user at domain.com*admin at domain.com'. 
Is that correct? 

Which leads me to my second question. I also run Ingo - which currently
stores procmail files via (Pure)FTP.   Gollem is also used, and is the
VFS provider.  I could alter the SQL query in PureFTP to trim the username
prior to running the auth and dir queries - but how would I get the $userId
reflect the original username?  The authusername hook? 
How does that interact with the postauth hook?  How often is it called?

Would I need to save the original username in a custom session var in the
postauth hook, then call the authusername hook (somewhere?) to switch the
username back for VFS/FTP use? 

Confused...  :)

Rick