Belts (if they do alarm) need to be taken off as to watches and cellphones.

A simple strategy would be to do as follows:

Present the BP & I/D checker your passport and bp as you always do.

if you can do this prior to entering the line, the better but I remove my watch and cellphone and put them in an inside pocket of my jacket which is then folded with the items "inside the fold and not on top and then placed in the little grey bin. You can also place you passport holder (with your BP and passport back in it as you no longer need it to go thru the WTMD) on your jacket before you fold it. As to your belt, if it's a money belt I would pull the cash and put it in my pocket (or a pocket of the folded jacket) and then put the belt in the little grey bin.

I know it sounds like a lot to do but you can actually get almost all of it done between showing your I/D and placing your items on the belt adn you should not be asked for I/D or your BP again unless you lucky enough to be picked for a gate search