Request-URI outbound will not change

I have a need to on outbound calls on on Tie trunk t send a specifiv RURI as @MyTrunk.com
I have done about all I can to et this to cooperate and nothing changes. Essentially it must be as shown below. I have tried using PJSIP Adding
trunk.MyTrunk.com to SIP Server (No Port)
in PJSIP advanced
Domain = trunk.MyTrunk.com
Proxy as sip:my.proxy.com:5560;\lr

and various other methods to know avail. Either Ring No Answer or Loop detected as the Request-URI never changes from my.proxy.com:5560 to what I need

Request-Line: INVITE sip:[email protected]:5060 SIP/2.0
    Method: INVITE
    Request-URI: sip:[email protected]:5060
        Request-URI User Part: 1234
        Request-URI Host Part: trunk.MyTrunk.com
        Request-URI Host Port: 5060