[Asterisk-Users] sip-sip

[Altus Snyman]

Good day all
We have a asterisk server running sip for about 20 users
We have a client running a unknown sip server in a different country
I phone the guy there and he gave a a account(username+password)
What I want is if a users calls the number of that country it should be
send to the sip server on that side?
What do i need to do on my side?Sip.conf and extensions.conf!
Something like this?
exten => XXXX,1,Dial(SIP/username:password at ipaddr/${EXTEN}@ipaddr) 
is there something that I should do on sip.conf ore something?
Please Help
Thanks
Altus