Using a second ip for mail services?

[hermestrismegistus]

A couple of days, my server has been abused by outsiders to send spam trough my ip. For that reason my ip got blacklisted. Although after some upgrades of the software the problem seem to be solved now, but still need to get removed from some of the blacklists. Therefore my isp gave me a second ip. So i could use this ip for outcoming and incoming mail.

My question is, how can i configure the mail system to use the second ip adres they gave me? Btw, i have used the perfect server setup for debian 6.0 to configure my server.