asterisk users - May 2016 - PJSIP outgoing INVITE and "contact" value

asterisk 13.8.7, PJSIP.

One VoIP provider requires a specific value in the field "contact" of
a
INVITE.

What setting does indicate the value will be in this field (instead 
"asterisk")?

Thanks.


currect settings (with templates):

[srv_d22778](srv-auth)
username=0000999xxxx
password=secret
[srv_d22778](srv-aor)
contact=sip:0000999xxxx at reg.dc-tc.com
[srv_d22778](srv-endpoint)
accountcode=5100
from_domain=reg.dc-tc.com
aors=srv_d22778
outbound_auth=srv_d22778
[srv_d22778](srv-registration)
outbound_auth=srv_d22778
client_uri=sip:0000999xxxx at reg.dc-tc.com
contact_user=srv_d22778
endpoint=srv_d22778
server_uri=sip:reg.dc-tc.com

INVITE sip:79265xxxx at reg.dc-tc.com SIP/2.0
Via: SIP/2.0/UDP 
85.142.148.80:5060;rport;branch=z9hG4bKPj05fd6429-c1a3-4bfb-87f8-df094c6532e4
From: "0000999xxxx" 
<sip:0000999xxxx at
reg.dc-tc.com>;tag=2b3456b9-8adc-4413-8012-98de85f949a8
To: <sip:79265xxxx at reg.dc-tc.com>
Contact: <sip:asterisk at 85.142.148.80:5060>