I parked engine at no:1 cyl TDC, used specific locking bar to hold camshaft at TDC. I swapped the belt, wrapped a new one around all pulleys. I undid camshaft sprocket, left it in place so belt was able to rotate it if needed. I had a pin locking the pump sprocket through the face of the sprocket into pump housing, thus holding it at no:1 cyl feeding point. Tightened everything when engine at no:1 cyl TDC. Checked pump plunger movement to be 1,1mm at TDC. (I know it should have been 1,00mm's ,but this was an experiment since many have reported good results with 1,1mm timing.) I re-checked timing maybe 2 to 3 times over, handcranking the engine between checks.
I used dial gauge with magnetic base for pump timing. In all checks it yelded same result.
This is how I did it in my 1.9TDI engine some months back. Absolutely no probs with it at all. Been clocking many kilometers after that manouvre, maybe 10 000 km's.