removing zones from ADT system

[cl999@xxxxxxxxxxx]

I bought a house last year with ADT alarm. There is no monitoring
contract as far as I know, ADT has never hassled us about leased
equipment or continuing an existing contract. The previous owners gave
us the master code. It is not currently being monitored, though we
find the chime feature whenever a window or door has been opened
useful so that's what we use it for. There are 3 ADEMCO 5850 wireless
glass break sensors that I would like to remove from the system as one
has gone bad (seems to short out any 9V battery I put in) and the
battery has run low on the other 2. My question is how to remove zones
from the setup? Searched this newsgroup and came up with some useful
info, but none regarding removing zones. This is my setup:

Ademco Vista 20SE control panel
Safewatch Pro 2000 keypad (ADT)
Alarmnet Ademco 7835c wireless receiver

I saw one posting about Vista 20SE needing a keypad for setup, but
instruction was for a different keypad than mine. Any help would be
appreciated...