Kolab 2.3.4: send from multiple domains in Horde

[Alexander Haensch]

Hi Everyone,
We have migrated our Users from Kolab 2.2.4 to a new testserver with 2.3.4
In the old Horde it was possibe to change the from_addr field within
Horde and therefore send mails under different identities and different
domains.
In the new Horde system it is only possible to change the Identity name,
but not the "from: address".
The feature to send from different domains is important for us, as some
users send from a secondary domain in some cases.
Is it possible to enable this feature again? Maybe via a "hook"? As a
workaround it would be okay to send the users from_addr choices in a
config file and disallow user changes.
Has someone an idea how to solve this?

regards,
Alexander Haensch