How to Dial #7

Just got FreePBX working, and I have a Digium FXS card. It’s wired:

FreePBX FXS -> Home Automation -> POTS

What I need to do is to have my sip clients be able to dial:

DialTone -> #7

so that my home automation system will do it’s paging stuff.

It doesn’t work when I just dial #7, so there must be some config I need.
Any help is appreciated.