hendrik on 07 Feb, 2012 04:14 PM
the key to comment plugin is an analysis plugin. That means, when you select a song and then click Analyze, it will show up as one of the analysis options. Strictly speaking, it doesn't analyze anything. All it really does, is copying the key info to the comment field. So for the plugin to do any good, you need to do the regular analysis for keys and also the copying.
For Traktor to see any beaTunes key, you need to make sure that "embed non-iTunes fields into files" is turned on *before* you analyze anything. The setting is located in the beaTunes general preferences.
Regarding your last question - I'm no expert for Traktor. So I don't really know what it does.
However, beaTunes has an inspection, that is capable of embedding cover art that you see in iTunes but is not embedded in the files. I'd try to use that inspection.