I have done this modification from the photos posted by Toppel (thanks for your idea).
I want to tell here what I have done, maybe will help other readers of Detektor Forum:
- drill 2 x 2 mm holes at 17 mm from the edge in order to meet the holes of RC support, and using the original 2 screws to fix it.
-I cut straight (perpendicular) the stick of handle's support (originally it is cut at aprox. 45 degrees) at 5 mm before the second screw hole, in order to create a longer space for the main stick (to have bigger rigidity).
-fix the handle support stick in the second screw hole with 1 original big screw.
-press the main stick till meet the handle stick.
-drill a 3 mm hole (3,1 mm is better) centered in the second hole place of former screw hole (with the main stick inside, of course

).
-screw the second big screw into this hole. That's it!
Must change the position of the stick into the coil: just rotate it 180 degrees (at HF coil you will see the wire, but no problemo

)
Advantages:- and it feels that the 22 cm coil doesn't exist, it is like you have just the stick... (nice feeling). With the 28 cm coil it feels the same as old position... but I didn't test it in the field yet.
-The rigidity of this montage is very good.
Disadvantage:- I tend to hit my right leg with the main stick (probably for this reason, XP done S-shape for the stick...), or I should synchronize the walking with the hand's move.
I hope you will understand properly because I am writing in English (sorry).