Calling ID Forwarding

Hi all,

I have problem with calling ID forwarding.
I am using Asterisk together with SER.
SER is my primary SIP Proxy and asterisk works as a application server.
My call flow is as follow :

|-----------------| |---------------|
| Asterisk | | SER |
|-----------------| |---------------|

When I send INVITE to userC@YYY.YYY

My problem is that when the asterisk is resending the message to user userC in the “FROM:” field I have “asterisk@XXX.XXX” instead expected original “userX@ZZZ.ZZZ”.
How to configure the asterisk to forward original calling id instead inserting his own.
Any help is very welcome
Best regards,