I had the same Problem a while ago, so although not full conversant with the alarm system it might be of help.
I disconnected the power to the alarm, took off the control pannel front cover, disconnected the battery inside and then put a charged battery in there instead.
My strobe and outside siren started goin off here but when the charged battery was put in and the power reconnected the alarm came back to life and I could use it as normal.
hope this is of some use - I thought at the time if it didnt work - new alarm so no harm in trying!
Stu.k
July 2008