TIE Trunk Ring Tones

I have Asterisk integrated with a Toshiba CTX/CIX-670 via a PRI crossover. When calling from Asterisk to an extension on the Toshiba, the phones buzz as an internal caller. I am trying to figure out how I can have the call sent to the Toshiba and look like it’s an external call so that the phones ring instead of buzz.

Any ideas?

Asterisk 1.4

Thanks.