I just spottet that the files from Sound Ideas are Broadcast Wave File format and the sounds from Hollwood Edge are AIFF.
So I’m guessing that MediaBay uses some sort of metadata contained in the wav files to find.
EDIT
I’ve found out that BWF descriptions are set and used to find the sounds in my Sound Ideas library!
But since the Hollywood Edge sounds are in the .aif format there aren’t any ways to set the same attributes, are there?
I’m thinking af ripping the sounds again, this time in .wav. After all it’s just 5 CDs containing 99 tracks each.