you buy some metal (cromoly is what i sugest) http://www.onlinemetals.com/merchant.cfm?pid=7341&step=4&showunits=inches&id=250&top_cat=197 and you take an old fork steer tube and cut it off teh fork. renforces it. then put it into teh stemm and bolt it. then put them stem and fork tube that are now bolted toghter inot the metal. and bolt it. then you have some barrs.
you have to do this because the inside of teh ada stems are 1 1/8 and the fork tube is 1 1/8 so its impossible to get metal that will fit