I believe
this thread might be useful to you, although it's for a diesel engine. But essentially you'll be wanting to do the same, you'll need an auxilliary belt the correct length to skip the air-conditioning pulley.
If you can't find one from Volvo then try Renault. These engines were fitted to the Megane, I believe. So that'd be worth checking out too. Unless yours is the mitsubishi GDi engine, in which case give them a try.