Asterisk IAX Trunking Services?

I was wondering if someone could point me in the right direction here. I am looking for an IAX service provider that I can port an old business cell phone number to. Does anyone know of any service providers that can port number rather than just assigning you a number from a pool of your choosing? The only reason I would like an IAX trunk over SIP is that our firewall here does not play well with SIP. So sorta like Vonage where you can keep an existing number but using IAX trunking instead… I have looked at some of the providers pointed out on www.voip-info.org but all they mention is outgoing calls only or DID pools. Nothing about porting a number.

THANKS,
A.J.

no one?

did you try VoicePulse? They port numbers to IAX trunks.