Yes, that is exaclty what it should do, or isn't /dimp the replacement of /imp?
Wouldn't my suggestion do that? Did you try?
Cactus
It's possible to use this url: http:<server>/horde/dimp
I have webmail.domain pointing to http:server/webmail
I'll try to change on DNS from /webmail to /horde/dimp as a temporary fix.
This will help on external access using DNS resolution. For internal one, they will have to choose DIMP ... at least for now.
Regards
Jáder