omitting zones on a accenta/optima lcd alarm remote?

I have a pir in my integral garage which I want to omit for longer than 1 period. Is it possible to do this with the user code or do I have to use the engineers code. The only way I could find was to make the garage an unused area? then the zone number isn't visible using the user code. As I have no other parking place I have to usethe garage all the time, so I have to get out of the car, unset the alarm before driving in, which is a complete pain, doing it several times a day. Can anyone help. I have both manuals am I doing it wrong or can't I do this with the particular alarm, the electrician said I could, but he'll charge me if I call him out he's not been the most helpful of people.