SIP problem, WM5 does not accept expires headers

Hi,

We are trying to get WM5 working with an Ingate firewall through a NAT-T
connection.
The problem is that WM5 does not seem to understand the "Expires" header
that Ingate sends out which prevents it from registering. We have also tried
to embed expires in our contact-header but WM5 ignores that too and just
keeps on sending REGISTER packets to the Ingate.

Any ideas? Any reg-hacks out there?

Regards,

Tony