Aastra 480i and FVC-100 (Not registering & hence "No Service")

Hi,

I have some Aastra 480i phones and I set the mac address in management console, choose Fortinet 480i and the phones get all the configuration data, but they do not ever register. With this the displays all show "no service". I read that if it is a Talkswitch/Fortivoice 480i phone it will work fine.  Phones have application version 1.4.2.3000 and 1.4.3.1001. I assume there is a block because they are not Fortine, but my understanding was these were just re-branded from Aastra to Talkswitch.

Any help would greatly be appreciated here on this!

Thanks everyone for reading!

Paul