Asterisk between a Clarent Softswitch and any SIP gateway?

Hi all,

here is my question.

One one side I have a Clarent CC5M Softswitch which can talk only to registered SIP gateways.
On the other side, I have a SIP gateway, which can’t register itself into the CC5M, but has a static IP. It can only be configured to directly trunk calls to other gateways based on the called number.
Obviously, the two can’t talk to each other.

So I am looking for a piece of software which would on one side accepts calls from the trusted IP of the SIP gateway, and on the other side would register itself into the CC5M, allowing me to proxy calls on both directions

Can Asterisk do this ?
If not, do you have any ideas to do this ?

Thanks a lot