dia: Thanks!! That's pretty much what I did. However, the cover is not exactly secure. A slight nudge, and it pops out at the bottow-right corner and falls away! It's as though the boot (I mean, trunk) liner at that point is too far recessed or something.
Ah well. It's not so bad that it will come off during normal driving, I think. It's something I can live with, anyway.
Thanks again for taking the time to help!