iPhone 5 not syncing with iMessages in Mountain Lion

I have an iMac running Mountain Lion and an iPhone 4 running iOS 6. They synced perfectly with iMessages. anyone who text me or I text them showed up on both my iMac and iPhone 4.

Well the problem is that I just got my iPhone 5 in the mail the other day and I cannot not get it to sync with my iMac for the life of me. I did a lot of research for solutions and I tried them all.

Yes iMessages is turned on. Yes my Apple ID account is logged into both and on. Yes my "Send & Receive" setting in my iPhone has both Adresses on; My phone number (checked) [but grayed out???] and my email for Apple ID (checked). thats for the "You can be reached by iMessages at:" section. and in the next section "Start new conversations from:" I have both number and ID there also but only my phone number checked because you can only check one. If I pick my email everything works fine and my problems are solved until I leave my house and dont have wifi anymore and I cant send or reseive iMessages at all even though I have 4G going and the internet is working on my phone. So I am forced to check the phone number so i can get text. Either way with the iOS 6 software, your apple ID is linked with your number so this should work. and it worked on my iPhone 4. I really believe this is a problem with just the iPhone 5. all the other fourms have answers that work for the iPhone 4 and 4s.

I tried hard resetting my iPhone 5. I turned iMessages on and off and hard reset and back on and no help. I waited the 24 hours after I turned iMessages back on and nothing.

So does someone please have any solutions that I have not tried yet?