I've tried using this site's search and have browsed the technical reference section and found no answer, so forgive me if I've missed something. I've also looked through my shop manual to no avail.

I've got a motorcycle/atv jack (http://reviews.canadiantire.ca/9045/0091015P/motomaster-motomaster-1-500-lb-m...) and I don't know where to locate it on my 2007 S40 to lift the whole thing off the ground. The points of contact with the bike are 2.25" wide, 9.5" centre-on-centre. I'm finding it difficult to place the jack without the exhaust making contact with the jack; I don't want the exhaust bearing weight, obviously.

Any advice out there?

I put my jack under from the side stand side, with the lift arms stopping just short of the muffler after going under the bike.

You have to put the front jack pad just short of the side stand which puts the other jack pad off under the swing arm.   But you can find a neutral lift position back there with a little hunting and fiddling (mine rests on the California charcoal canister).   Some add a piece of board to go from solid to solid so the jack lift arm in the back has something to hit because a lot of bikes don't have that California canister on them.

Key thing is once you get the bike up in the air you have to rope it to the jack stand in two places per side to keep it from falling off the jack stand.  

I use the foot pegs and the buddy pegs on each side for my tie down spots and I leave the jack about a half inch from "full up" when I tie it down then I use the jack itself to tighten up the ropes by lifting it some more.

Warning:   your jack stand has wheels and you will attempt to roll the bike around eventually.   If it isn't tied down to the jack stand it will tip over .....