I think that if you're asking people how to model a bow and wondering if you need something more complex than Milkshape, you have no idea how to model at all, and are trying to weasel a free tutorial out of other members of the forum, or maybe trying to get a freebie even. Let me ask you, have you even attempted trying to do this in Milkshape? I am in charge of a medieval mod for the game engine Sauerbraten, and have to model all of the weapons, and look what I did in Milkshape, in probably about a day less time than it took you waiting for a reply.
No you can't have it. My point here, is try it yourself before you go asking a simple question that you can quite easily discover on your own. I'm sorry if that came off sounding a bit rough around the edges, but it's the bare truth. Mods, if you thought this post was a bit too harsh, I'll gladly edit it out as soon as you say the word.
-Postal