How do I disable SIP ALG on the XB7

We are using UCX VOIP at work. It stopped working once I got the new gateway. Their IT department said 

"SIP ALG modifies SIP packets in unexpected ways, corrupting them and making them unreadable.

This can give customers unexpected behavior, such as phones not registering and incoming calls failing.

SIP ALG modifies voice and fax packets to make them appear as if they have a public IP address and are not behind a firewall.

All routers need to have SIP ALG disabled < This setting can be lock/hidden on some devices."

I have looked through every page in the settings and I can't find it anywhere.