Wow, 50 Meters?! I run mine on all the time, when the dims are on anyway.
As for the looking for wireing diagram and all, My oppinion is that relays are good, but not necessary depending on the size of fogs (amp load and draw). Granted, with the EDM switch everything looks like it is factory and that is definetly the way to go, but will take you more time to do.
To do a full "stock" route and wireing, you will have to open your harness up starting at the fuse block on the pass side fender well next to the battery. In the fuse box, there is an open whole for a relay that you will have to source a plug, and relay for. It shouldn't be to hard to find one from a DSM though. After you put the 3 or 4 wires that they require, you will have to run them all the way through the loom into the driverside where the harness comes out at the fuse box.
One (maybe 2) of the wire(s) will keep going back to the rear of the vehicle following in the exisisting loom. Once you get to the back, you wil split out of the loom and have to splice the wires into your 2 tail light plugs. You will probably need to source these aswell, because they are going to require another wire source because of the dual filimant bulb (I belive) instead of the single. You shouldn't have to worry about the other wire(ground), since it is already in the harness and attached to the plug.
Now, back to the fuse box, you will need to find the open fuse space and insert the new wires with the proper terminals wich you could also source from a DSM. I belive that the fuse will be a 20 or 30 AMP.
Then its time to wire in the spitch. I'm not sure waht the plug is like, but if you already have one, then you are golden. The wires will go on to the wires from the relay, and one going to the switch. Then there should be 1 or 2 more from the switch that are for illumination. These will have to be run into the wireing for the dash illumination. You will have to tie your loom for this into the exsisting loom to give it the stock apperance. After you get all the wire in the appropiate looms, make sure that you have all the wires hooked up correctly, becaus eif you dont, the wires could surge and get hot. This inturn will give you a really nice wire fire and destroy the whole job, along with your car at 2am in the morning (ask me how I know....)
If everything works like it is supost to, then tape the loom back together, and re tuck everything and button it up.
This information, is purely from tearing apart a bunch of harness' from many different vehicles over the years. I can not gurantee that this is exactly the way that MITSU wires them, but this is how It should be done from what I have seen.