How can i tweak the grandstream to acccept "@" sign


I am trying to setup a sip trunk which comes with a username that has got an @ character for example but the ucm 6510 does not allow special characters like the @ sign in the username section.
I am told that there is a way to add this character from the backend but i have not been succeful in doing so.
Do you know how i can solve this?



thanks, i have done that. awaiting their reply


The only grandstream assistance is that,
If you are not possible, nobody on the forum can help you.