Anybody has a sample ser.cfg that forward calls to Cisco AS5300 GW?

I am using the Nathelper templet config file and got NAT +RTP relay works on IP2IP, but dont know how to work with PSTN through Cisco AS5300 GW.

where to put the forwording code.

I got some sample code here:

# is it a PSTN destination? (is username nummerical and does not begin with 8?)
if (uri=~"^sip:[0-79][0-9]*@") { # ... forward to gateways then;
      # check first to which PSTN destination the requests goes;
      # if it is US (prefix "1"), use the gateway XXX.XXX.XXX.XXX...
      if (uri=~"^sip:1") {
           # strip the leading "1"
           strip(1);
           forward(XXX.XXX.XXX.XXX, 5060);
      } else {
           # ... use the gateway YYY.YYY.YYY.YYY for all other destinations
           forward(YYY.YYY.YYY.YYY , 5060);
      }
      break;
}

I dont know if it can talk with Cisco 5300 GW though.

Where should I put it in ser.cfg with NAThelper + RTPreply support?

How to debug the ser.cfg, if i hear busy tone when i dial the PSTN number.

Thanks for your time,