Try and send to sip device without it being registered

Right here’s the scenario.

I have asterisk all up and running fine with 5 snom phones.

i also have another sip box that connects to gsm(irrelevant) the gsm phone i am trying is extn 1002. from the * box. i can place calls from the gsmbox(1002) to any other extension fine on the *box

Now the problem i cant call from the *box to the gsm, I can the other way round as i have set allow anonymous inbound sipcalls to yes.

as extn 1002 on the *box is effectively not registered i cant call it (IT FAILS AND GOES TO VOICEMAIL),

what i need to do is “fake it being registered”? is there a way of doing this or getting the *box to try even though the phone isnt registered? i have set the host=to a the ststic ip address of the gsmbox. here’s a copy of my config.

anyone help?

[1002]
type=peer
record_out=Adhoc
record_in=Adhoc
qualify=no
port=5060
nat=yes
host=192.168.0.52
dtmfmode=rfc2833
disallow=all
dial=SIP/1002
context=from-internal
canreinvite=no
callerid=device <1002>
allow=gsm