Host part only in Contact message

Hi all

I am trying to interconnect with a mobile operator that requires only the host part URI in a SIP contact message.

if I set the contact in message to false, the SIP contact returns:

what you should/expect to be receiving:

any ideas would be gratefully accepted.

Not sure with FS but it seems possible with SBC. You can reach out to us for further discussion and see we can do that.