Problem with SIP using TCP without SNAT

I have a problem whereby I am trying to load balance SIP traffic over udp and tcp to a pool of nodes that I have set up.

 

I have a virtual server set up using a SIP profile and it is using TCP as the protocol. I can get F5 to load balnce the SIP to my pool of servers over TCP when SNAT is set to AUTO MAP. Unfortunately with SNAT on the INVITE that gets to my pooled server looks like it has come from the F5 external IP rather than the actual client that sent it.

 

I need the source address to be the client's IP in my deployment. If i turn off SNAT, F5 does not bother passing on the SIP to my pool of servers. I have wiresharked F5 and can see the INVITE coming in from the client. I have tried to look for something in the logs but cannot find anything useful at all. ( I am probably looking in the wrong place!)

 

I am not sure how to make tcp work with snat turned off. If I use UDP, the invite source address is the client as I want it.

 

Can anyone help?

 

THanks

 

Hugh