Yes, currently I have two domains that I can send and recieve using their own settings. You have to make sure that you set up the second domain as a new organizational unit. When you do this you need to add a group to this new unit. Once you add a new group goto the properties and then goto E-mail Addresses. Here is where you want to click new and follow the prompts entering your domain information. Once you finish this you can close out and then we need to head over to exchanges system manager. Double click on recipients then on Recipient Policies. You need to add a new policy and then click on email addresses. Once you get thru entering your new domain information make sure that you have your new smtp address checked and now if you have your dns setting correct you should be able to add new users with your new domain name. If you have any questions just let me know.
Andrew