Paolo, I just purchased a SBE Camo (LH) and used it for the first time on opening day of dove season (Sept. 1st). I did not have a single failure with the gun using 1 1/8 oz. loads. Benelli recomends using only 1 1/8 oz. or heavier loads for the first 100 rounds until the gun is well broken-in, then you can use light target loads.
I don't think the Ducks Unlimited Edition is mechanically different than the standard SBE so you should have no problems.
Happy Shooting!