Plugin folder icons

[RextheC]

Hey guys.

I would like to change the folder icons of my Plugin folders.
Picture and video plugin folders were changed good by using the context option: set thumbnail.

But in music and program section nothing happened when i do it the same way.
Have also tried with a folder.jpg directly put in the plugin folders, but without success.

Its not a big prob, but would look even better with individual thumbs.

If i also have to paste debug log, let me know, of course i will do that immediately. Perhaps someone can take a look at this. Hope for help.
Thx

[RextheC]

Have also tried with .tbn instead of .jpg but with the same result.
So here are the log files:

Program Plugin log file
http://www.xbmclogs.com/pbzkblxld

Music Plugin log file
http://www.xbmclogs.com/pkfli8owq