Honda Accord Forum - Honda Accord Enthusiast Forums - Dash installation questions -- new single DIN unit into 91 Accord

This car was stolen over a year ago, but we got the car back again 3 weeks later, minus the CD player/radio. The stolen part wasn't a factory unit, but an aftermarket unit the previous owner had put in (by Pioneer, but I can't remember which one). So the thieves may have taken out more than just the player--they may have removed mounting hardware. They were "nice" thieves--they didn't damage the dash at all (although they cut the radio away from the previous wiring harness rather than just unplug it--I didn't say they were bright thieves).

The hole in my dash contains just the following bits, as seen on this diagram:

#20--bracket, auto radio.
http://www.hondaautomotiveparts.com/...m401_b1601.png

Now, on to my question.
I just received a new Stereo receiver (thanks Santa!). The new unit is a Sony DSX-S210X, from Crutchfield with dash kit and Honda wiring harness. I have already wired the radio harness to the Honda harness, and plugged the unit in to my car to test it. It works great so far--got sound in all 4 speakers.

Here's the problem part:
The plastic receiver mounting bracket (In-dash Receiver Kit--Item# 120997888 from Crutchfield) doesn't fit into the hole in the dashboard. It's meant to be Honda specific, but it's a bit too wide, and has long plastic tabs projecting back into the dash, so it doesn't snap into place as it should, and the metal DIN sleeve barely fits into it. There is a rear support piece (shaped like a square bracket "[" which I have mounted onto the #20 bracket listed above--but do I need it? Does it prevent the unit from sliding all the way in?
Also, I believe that the DIN sleeve is meant to help with theft prevention, yet the bendable tabs on that sleeve will only be stopped by that plastic bracket. Hmm..that's not secure at all. A good pull will just rip the radio right through the plastic mounting bracket. Also, it has a silly 1/2 DIN space below it, where there should be a pocket. (See part #21 above)

So, knowledgable people, where can I get a better fitting bracket, which is more secure (I'm willing to put in a backstrap, since there is a hole for it)? Can I get the pocket back? In the original mounting (from the picture above), what actually held the player in? Was the receiver unit screwed to something?