Configuration problem with "non-address-login"

[hypercube]

Hello everybody,
I installed Roundcube a fe days ago and I have to say, this is the best webmail client I have worked with so far.

There is just one thing that I dobn't udnerstand. It seems that other users had similar problems but in the posts I found they either didn't post a solution at all or the solution does not fir to my specific problem. So I hope that maybe someone here can hgelp me out a little bit. Thanks for any help!

My mailing environment is as follows:
- currently one imap server, address: imap.mymaildomain.com
- currently one smtp server, address: smtp.mymaildomain.com
- in future, there might be more servers, like imap2.mymaildomain.com oder smtp2.mymaildomain.com
- I host mail boxes for many different domains on these servers. However, I have my own postfix installation on another server that does the complete "routing". For example, one of my users has the domain "mail@userdomain.com", the my external server redirects all messages to "mailboxid@mymaildomain.com". So an example for an postbox adresse could be: "12345@mymaildomain.com".
- So to login with Roundcube, I have to enter "12345" and then the login works. This is great so far.

Now my questions:
- However, when I want to write a message, it says that my address is "12345@imap.mymaildomain.com". How can I get "mail@userdomain.com" here instead?
- Can I create a login field in which the user can enter "mail@userdomain.com" and logs into the correct mailbox "12345@mymaildomain.com"?

Thanks again for any hints, help and support!

[hypercube]

Nobody? Any ideas? Is this place dead?

[methilnet]

Now my questions:
- However, when I want to write a message, it says that my address is "12345@imap.mymaildomain.com". How can I get "mail@userdomain.com" here instead?

Have a look at $rcmail_config['mail_domain'] = ''; in main.inc.php.

- Can I create a login field in which the user can enter "mail@userdomain.com" and logs into the correct mailbox "12345@mymaildomain.com"?

Maybe this is for you.
// Path to a virtuser table file to resolve user names and e-mail addresses
$rcmail_config['virtuser_file'] = '';

OR

How about having the user login with 12345@mymaildomain.com instead of mail@userdomain.com?
If 12345@mymaildomain.com is the real mailbox why use the virtual one to authenticate?