Use for Telephone calls: On
Username: GV[insert your number here]@gvgw1.simonics.com
Password: [as provided] (secret)
Advanced:
Username: GV[insert your number here] or Username (ex.GV1234567891)
Transport: UDP
Outbound proxy: gvgw1.simonics.com
Port: 5060
Discover public address: On
Loose rouing: On
Keep-alive period: Automatic
Auto-detect STUN: On

Save and you're good to go

Note: ignore the registration string. You use that for asterix only