non penetrating hits on size two and above vehicles

I hope that the list grunts might be able to explain this for me please. 

If a size two or above vehicle is hit with an infantry weapon, but fails
to
penetrate, do you still roll for a non-penetrating hit?  If you do, this
makes vehicles very weak, you have a one in three chance of disabling
the
vehicle.  

Help

Slim

Simon LeRay-Meyer, MCSE
Network Manager
Victorian Dairy Industry Authority
Ph:  03 9426 1687
Fax: 03 9428 6111
Email: sleray-meyer@vicdairy.vic.gov.au