Can I disable rport on outbound TCP SIP requests?

The rport Via parameter is of course a good thing to set on outbound SIP requests when using UDP but I think it's a bad thing when using TCP.

This is because outbound TCP requests use a dynamic source port and the UAS will not be able to establish a new TCP connection to this port if it needs to, for example to send a response after the connection has been closed. 

In most cases this won't be needed - hopefully the original connections remains open - but with mobility, firewalls, etc, connections do sometimes get closed between initial request and final response.

Regards,

Richard