If anybody might be interested, i got an email today from Vbelt supply and they are having their summer sale on V or wedge belts. They stock the correct metric belts for the isuzu diesel. Ive ordered from them before and had real good luck.
Buy V-Belts Online - V-Belt Catalog
I believe the spb1260 is the correct belt for the alternator. Not sure about the Ac. Discount code = SUMMER12. They have really good prices anyway, without the additional 12% off on sale. So if anybody needs to order some spares.......