Register SIP trunk w/o authenticaion?

Trying out a new VOIP provider. They are able to provide sip trunking and it’s authenticated by our source IP. There is no username or password. How would i register and use this with freepbx?

type=friend
host=provider.ip.or.url
dtmfmode=rfc2833
disallow=all
allow=ulaw
port=5060
fromdomain=provider.ip.or.url
insecure =port,invite
canreinvite=no
context=from-trunk

Thanks jfinstrom,
do i need to use anything in the registration string?