Im trying to make SIP to H.323 calls, redirecting from SER to Asterisk and then to GNUGK

I tried hard to do it but the documentation is not very explicit.

As SIP Im using a ZyXel Prestige 2000P and X lite, and as H.323 im using an Aethra.

What do I need in the SER configuration (ser.cfg) to redirect the H.323 calls to asterisk?

I tried the rewritehostport:

rewritehostport("Asterisk_ip : Asterisk_port");
t_relay();

.... but Asterisk didnt received the calls.

Can anyone tell me how to redirect H.323 calls to Asterisk?

Thanks in advance

Joao Pereira