Movie coverart not shown for movie stored in BD-R disc

Hello, first timer here.

I have a bunch of movies stored in a folder in my hard drive. They all have movie covers (which I grabbed using the F3 function)
I decided to burn some of them to optical media to save some disk space, but I found out the covers do not "stick".
First I used F3 again as not to touch what I already had in the Video Database, the movie cover was shown on screen after a search match was found, but as soon as I returned to the folder where the movie file is stored in the BD-R disc (by pressing ESC), the selected movie cover was not displayed in the video list.
Then I edited the database entry for the movie, since it was still in the original location in the hard drive, adding the path to the movie file in the burned disc. Even that way the cover was not displayed when I opened MP and navigated to the BD-R folder.

Any ideas why MP is not treating removable optical media the same way it does with a hard drive? I searched the forums and the manual but could not find a clue for this behavior.

I am running MP 1.7.1 (hotfix) on Windows 7 x64

Many thanks