So you wanna use XTension to control your alarm here is a start. You will need to setup a DIY interface with these settings the proper baud rate.

Now for the code needed to for the alarm to display what its doing and using with Web Remote. Just replace all the Received Data script with the code below. UPDATE: Add Pseudos for all your Zones like this

 

I hope that helps.

The devices are pseudos that send data to the interface like Arm and alike.

UPDATE:

Create a pseudo with…

send data “<YOUR PIN><2 is away 3 is stay>” interface “<the Name Of your DIY”
so something like this, if your PIN is 5555
Pseudo Alarm Away
The on script would be as below no off script.
send data “55552” interface “Alarm”
Pseudo Alarm Stay
send data “55553” interface “Alarm”
Then for the Disarm pseudo you would do an on script like this…
send data “55551” interface “Alarm”
turnoff (thisUnit) in 1
if (status of “Alarm Stay”) is true then turnoff “Alarm Stay”
if (status of “Alarm Away”) is true then turnoff “Alarm Away”

The Vera solution is much more eloquent, but to get in the trenches and make your own can be more exhilarating I think.

Have fun!