How to get flash on fxo line to work

Hi. I am using freepbx 2.3.0 and I have a Digium x400p with an fxs and fxo module. Now what I would like to be able to do is use the asterisk feature which allows you to flash the hook on the fxs line and press *0 to flash the fxo line. Ihave changed the speed dial prefix from *0 to *9, but all I ever get is Allison saying that this feature is not enabled on this line.

Any assistance would be appreciated.