I called VW, and according to them, the nipple is part of the hard plastic line. This assembly was discontinued in January of 2010. Should anyone run into this problem and you aren't able to find a used replacement, here's my fix.
After cleaning the broken bits out of the booster grommet and hard line, I went to home depot and bought a PEX reducer, 3/4" to 1/2", I believe. I ground down the ribs on the 3/4" side and using a liberal amount of silicone spray, worked it into the grommet. It will feel impossible to make fit, but it will. Next, use either a heat gun or (carefully use) a propane torch, slightly heat the plastic line at the tip just enough to soften it up, then slide it onto the 1/2" nipple sticking out. Road test to confirm fix. Drink a beer and celebrate that you just fixed your vacuum line for $1.69.