Relay single Domain to relayhost?

[polysign]

Hi there,

I have a simple. but yet frustrating question/problem to solve...

I have multiple domains setup on my ispcp server. One client however uses his own Exchange Server locally (his office). Now I want to relay all incoming mails for his domain to his own Exchange server.

So I setup a transport map:
hisdomain.tld smtp:IPofEXCHANGE

and put it into a transport_map in the main.cf.

That does work if I the mail address I am sending to is setup in the alias.db / in ispcp as alias or mailbox account.

How can I solve this without having to setup a mail account in my ispcp box for every account on the exchange server?

Please help