Scooterotica

I recently got a 2nd hand giuliari seat (no strap)after it was fitted the rear closing pin seemed to short to go into hole on rear plate catch.I looked in manual for tips & on page 231 (2nd edition) I saw a pic of front plate with a bracket between seat & frame should I have a bracket to mount seat on or do some go straight on the frame & could that be why it won't lock properly I put several washers under rear plate to raise it but still no joy.Any info greatly recieved

...tap the bit that stands up on the catch plate with a hammer so that it engages with the locking mechanism...loosen the bolts on plate so you can move it closer to engage....