[Serusers] using aliases

Howdy, I am trying to determine why a call won't connect when dialed using an alias. I'm running SIP Express Router v0.8.10 on FreeBSD 4.8-RELEASE. Below is the message the client (Xten X-Lite) is receiving and apparently discarding. It appears as though the call is being routed but I'm puzzled by these message headers. RECEIVE << 192.168.1.11:5060 INVITE sip:pyuska@192.168.1.25:5060 SIP/2.0 Max-Forwards: 10 Via: SIP/2.0/UDP 192.168.1.11;branch=z9hG4bKad62.cf628db7.0 Via: SIP/2.0/UDP 192.168.1.15:5060 From: yuska <sip:pyuska-ppc@shitworks.com>;tag=585911808 To: <sip:5315@shitworks.com> Contact: <sip:pyuska-ppc@192.168.1.15:5060> Call-ID: 06E1E114-22A1-8B9D-2891-72E17E9928EA(a)192.168.1.15 CSeq: 12625 INVITE Content-Type: application/sdp Content-Length: 283 Do I need to configure the SER server re-write the To: address or is the client misbehaving by not responding to the Contact: ? Any light you could shed on this would be appreciated. Phil