The reply on the tailpiece is correct.  It is not available as a replacement part.  I buy the general purpose replacement VW lock and take the tailpiece off and put on the old cylinder, as the correct Vanagon cylinders are getting scarce.  Not terribly hard to change with a 1/16" drift.  When I replace them, I go ahead and pull the lock apart and clean/lube it while I'm in there.
Steve Sandlin, Registered Locksmith
Steve's Lock Shoppe
www.steveslockshop.com