I managed to make it work
This was the info callcentric gave me.
"We successfully registered the 3CX softphone on a Nexus One connected to wif so it should work without a problem. Please use the following settings in your configuration:
User: 1777xxxxxxx
password: [password you chose upon sign up]
Internal Server: callcentric.com
External Server: callcentric.com
STUN Server: [leave blank]
You should be able to leave the rest of the settings as they are by default. Once you've entered those settings click Save at the bottom then hit the universal back button to go to the dialer server at which point your softphone should register.
If you have any other questions please feel free to contact us at any time, Thank you."
Hope this help