Rattle on rear cover

Hi All,
I've got a rattle (tinny type vibration when I tap it) right at the seam of the rear cover assembly black plastic cover (with the Honda decal on it) and the red plastic of the brake light cover.  Hoped that the cover would come loose by itself but it requires the whole rear cover assembly be removed.  I didn't want to get that involved.

I was, however, able to pry the RH side of the black panel up a little to get a bit of a peek back into that cavity.  Didn't provide much of a view since I couldn't pry up high enough without risking a break.  Was contemplating getting a can of weather sealant foam to inject back there to help provide some pressure to the backside of that panel and maybe stop the rattle/vibration.  

Tried prying up right at that seam but no luck there either.  Just don't feel like tearing that area apart for a rattle and not sure I could even get in there if I did.  Any other suggestions would sure be appreciated.

One would be NOT to use the foam sealant.

An ongoing update... I finally broke down and pulled the two bottom bolts on that assembly. Wasn't terrible like I thought it would be. Just the black panel and the light unit came off... not the big support bracket that resides under there. Pulled the bulb sockets out, removed the cover mounting screws, and then had to work at freeing the black panel from a stubborn locating lug at the seam before it freed itself up. Now will have to think of something creative to cushion those two areas. We'll see...

Maybe some sticky back foam strips like they use on house doors, cut to length cut to thickness.

Well, job is finished. Wound up using some "Gorilla" tape to make a spacer of sorts. I believe that helped after all was said and done. Plus also attacked the small black cover 'under' the brake lite also.
Used the same tape there also. Then finished up by respacing the area under the top box to eliminate any added noises there. Will take it for a spin tomorrow and see if it all was worth it. Oh yeah, I also removed the end of the muffler to retighten the 'chrome' pipes I had installed. Found out two of those end cap screws were loose too. Guess it just never ends...

Hi DickO, Under my GIVI top box I use that rubber "Grip Liner" shelving liner and put a layer under it to take up any space and eliminate vibration. It seemed to work pretty well. I think it does wear out after about a year and I'll have to replace it again this season. But it's cheap and easy to cut so no big problem.

Yeah Dale, I had used a similar material the last time I messed with mine plus also used some pink plastic insulation stripping normally used between a frame wall and foundation during construction.  This time, I used just the pink insulation, triple folded and located a little more strategically so that I didn't have to cram a bunch of other stuff with it.  So far, so good.