if both power cables are reading like you say must be the starter, I will get a picture up of how mine failed.
 
starter.jpg
 
replaced the starter today and fired up first turn of the key..but found a leak from the metal coolant pipe which is routed round the cylinder head, spraying coolant directly over the starter. :(

still, thats the starting problem fixed. my starter motor/solenoid link was still intact and looked ok. heard from a VW Specialist this is a common fault tho