It turned out that I have plenty of free space under the fuel tank.
I'm a kind of guy who always likes to carry some tools on the bike, just in case.
This two combined resulted in creating a useful toolbox mounted under the tank.
The box itself is made of a PVC pipe, an idea already tested in my previous bike and working well :)
This piece of metal on the bottom serves as a stopper for the pipe and at the same time is a fuse box holder.