Getting chrome wheel trim back on

[Brendan The Spit]

So one of the wheel trims just came off mid-trip. Fortunately I noticed and stopped, reversed, picked the bugger up from the hedgerow and brought it back home. It's one of those circular rim things, a bit like this but not exactly the same: http://www.rimmerbros.co.uk/Item--i-GRID010670

But I cannot get it back on!

The closest I've come is to squashing it  out of shape so that I get all but one of the metal hooks located, then I'm trying to lightly tap the last one in with a screwdriver or chisel and hammer combo, but it just pings out again. I nearly took two fingers off earlier so I'm not terribly keen to keep trying to do this the wrong way.

So what's the right way? I feel such a numpty not being able to do this. I've tried every which way but cannot make it work. Any suggestions?

[smithy]

Sounds like the clips are a wee bit knackered mate. I'd be tempted to have the wheel off, put it flat, and work on it that way.
Or chuck the chrome-y thing into the weeds. (I had a set of those and flogged 'em to Fire Bobby along with the steels I think, He might remermber a better/cleverer way to deal with them).  

[Bainzy]

Mine were like that putting them on as new items. Taking the wheel off the car makes the job a lot easier, and be careful you don't apply so much force you end up with a bent rim.

[Brendan The Spit]

Blimey, I wasn't planning on having to take the bally wheel off.

OK, I'll just have to keep trying - although they're nasty, nasty sharp things and I'm going to do myself a mischief if I'm not careful...