I agree breaking the old switch is the easiest. As I too cotnempleted how to get the darn things out then decided they were no good anyway so just break'em. I just romoved the front part of the dash, the part that just snaps in and out and the headlight switch IIRC then just push the old switch out a light bit then use a pliers to break off the round piece that holds it from going back into the dash. Then simply push it back towards the dash after you break it and remove it after you have disconnected the wiring. The new one simply snaps into place then reconnect the wiring.
Hope this helps.
Wheat Whacker
2001 Chevrolet 2500HD Crew Cab LB
1995 Chevrolet 2500HD Ext. Cab LB
6.5L Turbo Diesel HO (I know it ain't a DMAX but I can pretend, right)
Amsoiled from one end to the other
Road Warrior Class V Bumper with a "When I Grow Up I Want To Be a Kenworth" Bumpersticker