After going to the faq pages under cam position sensor which I think we are talking about, the responce to the leak you have is that you need to take the car to the Volvo dealer to have a new seal installed. From what I read of this there is so little room back there that Volvo had to come up with a special tool to press this seal in. If it's leaking as much oil as you say this would be the only way of repairing the problem short of pulling the engine.
I hope the bolt that you took out isn't completly stripped or you may have to have the durn thing pulled to repair the threads there as well.
Good Luck
Poolman