How to access wiring loom under the engine bay fuse box?

[soundsk]

Hi,

Shortly after buying my Cali, I ordered a GPS tracker/remote immobilizer to install in the van.
Ever since I've bought I've had it hidden inside the van because I haven't yet installed it in a definitive manner, mostly because I don't want to butcher the electrical installation and make a mess.

To install it I only need 12V from the battery and interrupt the fuel pump relay line.
I have located the fuel pump relay fuse - a 30A inside the engine bay fuse box, and after removing a plastic part inside the fuse box, the fuse holder comes out with all the fuse wiring attached to it, and I can clearly see through the hole that into the fuse box, that there what seems like a watertight compartment where I can see a whole lot more wires, but there would be room to install the tracker and it would be ideally close to the battery and fuel pump fuse, making installation simpler and cleaner.

What I can't figure out is how to get better access into that "compartment", because through the fusebox hole alone I can't fit neither the tracker or my hands!

Here is the fusebox in question, by removing the plastic part where the red meter lead is, the whole inside of the box comes out, leaving a hole where you can see into the compartment I'm referring to.

Any ideas?

Cheers! =)