[Serusers] handling multiple INVITE statements

Hi I am getting 2 INVITE per call, which is correct in my setup. I have IP phone ---> ser---> asterisk----ser----ip phone for various setups So when ip phone makes a call, to a internal extension, the call goes out via ser (INVITE 1) into asterisk, which then maps this internal extension to a external number and hence issues a DIAL sip/xxx statement (INVITE 2). All well and good Now should this not give two BYE's anyhow it gives one. The other thing is what to do with the two INVITES, should I be taking the INVITE from asterisk, or from SER, I think the former, BUT the BYE seems to match the tag for asterisk INVITE Iqbal