hi may be of help. I changed a timing belt on a galaxy diesel, most of the bits had v.w. stamped on them. the new tensioner had a strange little metal key with it, not unlike a sardine can opener.I couldn't figure out what to do with it, so I phoned the supplier. didn't know. eventually I e-mailed the tensioner bearing manufactures in canada. got a nice e-mail back which said" the key is only to assist in the tensioning as an aid to holding the bearing while you tighten the retaining bolt" then throw it away. I would suggest that if you look up the manufacturers web site they will be only too happy to help.( the people I contacted sent me a web address, and full instructions were there.) your engine is probably the same as the galaxy tdi, and we did not use any special tools, in fact all we did was to get the engine into a neutral position(off compression) then marked the cam pulley, crank pulley etc with a gold paint marking pen, released the tensioner bolt, took off the tensioner and belt, made sure all the marks were still lined up and put on the belt and tensioner, tightened the tensioner until the arrows lined up( on the tensioner, metal pointers) tightened up and that was that, started first time. no special tools, just common sense.