Looks like I had to live with it. At least for now. Or until my next trip to the East Cost of USA..
Anyway, not a big issue... the bass is absolutely functional, just a little hard in the 1-4 frets region.
I guess the raised nut explains the fact that the bridge saddles are slammed down. Otherwise the overall action would be very high. Fortunately the neck is straight, very stable and trussrod works perfectly.
Anyway, just for information.. how much would approximately be the cost of a shipment back to Italy from the States? I guess I could send the bass to you with UPS for about 150 euros...
Just in case I get the itch for a full setup, new nut and the such