[horde] from address

[manou]

hello,
I never know if my problem is common to many of the horde admin cause
I'm a very newbie to this application.

But, I could run horde3/imp4 under debian sarge from a .deb package.
The authentication is under a "multidomain" courier-imap on a remote
server. So, someone at domain1.com and someone at domain2.com can exist at the
same time. The default domain for horde is domain1.com. And when
someone at domain2.com want to log in to courier, his username may be
someone1 (due to a hack in courier...).

But my problem is that I want horde/imp to get the from address from
courier-imap mysql database according to the username. If "someone"
loggs in to horde, horde will "select email" in the mysql database
"where id='someone'" and put this email address on "From:" instead of
getting from the Identities or someone at defaultdomain (here domain.com)
imperatively. I could lock the from_address in the config file but I
could'nt find where in all horde/imp function could I hack to make the
request?

Is it already possible under horde or I have to modify the source-code?

Regards,

Manou