fwiw, I just tested with TAL (downloaded TAL podcast in MM, change the "Type" from "podcast" to "music"; and change the album artist and artist from "Chicago Public Media" to "Chicago Public Radio"; and set the track number to be equal to the episode number.
Then open the track in MP3Tag and Windows Media Player (I don't have subsonic installed). Both read the tag as expected.
Peke, when you tested this with subsonic, it worked ok?
Beta Testing for Windows Products and plugins
Yes it all worked OK on Windows version of subsonic. I'm suspecting that there is maybe a bug in ID3Lib on ajkessel Linux, as unfortunately my QNAP decided to not let me install one on it.