Davide,
First. This is very precise soldering and wiring. If you don't have experience with doing circuit board wiring, or have the right equipment, you may want to see if there's a friend who can do it for and with you. Also, doing this will void any warranty from SkyWatcher. OK that said. See my images above your pictures.. Start by pointing the LED itself the same direction it is pointed in mine. Pay attention to the R0 and R1 notations on the board. You have to attach (solder) a very small (preferably solid core) thin wire as I describe in the instructions. I tried to make the instructions very very precise. In theory, it would likely work soldering a wire to the back as well.. just make sure it's the same connection spot on the front.
Jay S.