ttshosting

Hi I'd like to offer free domain with any new hosting plan order BUT only for new clients. If I select the free domain option under Product/Services I don't see how to specify that this free domain is only for new clients. Before I was using a promotion code, the problem with that is that I want to offer the first month free on any hosting plan. How can I use two different promotions code? (FREEDOMAIN + FIRSTMONTHFREE) Can I setup a promotion code that do both offers? Thank you