Unfortunately Sigma Sam stopped working for Sigma in 2010 and has now stopped answering Sigma alarm queries.
From his last technical post on SIDC: "For advice on your Sigma alarm systems please contact the technical help desk at Scorpion Automotive on 01257 249928 or visit
www.scorpionauto.com for other contact details"
This is the technical section thread, which may contain the answers that you need. If not then searching the British SUbaru forums using his name will probably find your problem discussed.
http://forums.sidc.co.uk/topic/96215.../page__st__660
Simon