A/C Hose Leak ... need help reaching it
 

I think I have a leak in one of the A/C hoses (yellow arrow in picture) of my 2000 CLK 430, but it's in a location I can't easily get to (orange arrow in picture). The leak appears to be hidden behind the master cylinder in between the 'double firewall' separating the cabin from the engine bay. I'm looking for some direction on how to best change out the hose. Anyone have any experience with this particular part, and can give me some advice on how to reach it?

http://www.techcitysystems.com/acHoseLeak.jpg