I will provide an updated API interface file at a later date but here is what you need
public enum MetaDataType
{
TrackTitle = 65,
Album = 30,
AlbumUniqueId = 108,
AlbumArtist = 31, // displayed album artist
AlbumArtistRaw = 34, // stored album artist
Artist = 32, // displayed artist
MultiArtist = 33, // individual artists, separated by a null char
PrimaryArtist = 19, // first artist from multi-artist tagged file, otherwise displayed artist
Artists = 144,
ArtistsWithArtistRole = 145,
ArtistsWithPerformerRole = 146,
ArtistsWithGuestRole = 147,
ArtistsWithRemixerRole = 148,
Artwork = 40,
BeatsPerMin = 41,
Composer = 43, // displayed composer
MultiComposer = 89, // individual composers, separated by a null char
Comment = 44,
Conductor = 45,
Custom1 = 46,
Custom2 = 47,
Custom3 = 48,
Custom4 = 49,
Custom5 = 50,
Custom6 = 96,
Custom7 = 97,
Custom8 = 98,
Custom9 = 99,
Custom10 = 128,
Custom11 = 129,
Custom12 = 130,
Custom13 = 131,
Custom14 = 132,
Custom15 = 133,
Custom16 = 134,
Decade = 105,
DiscNo = 52,
DiscCount = 54,
Encoder = 55,
Genre = 59,
Genres = 143,
GenreCategory = 60,
Grouping = 61,
Keywords = 84,
HasLyrics = 63,
Lyricist = 62,
Lyrics = 114,
Mood = 64,
Occasion = 66,
Origin = 67,
Publisher = 73,
Quality = 74,
Rating = 75,
RatingLove = 76,
RatingAlbum = 104,
Tempo = 85,
TrackNo = 86,
TrackCount = 87,
Virtual1 = 109,
Virtual2 = 110,
Virtual3 = 111,
Virtual4 = 112,
Virtual5 = 113,
Virtual6 = 122,
Virtual7 = 123,
Virtual8 = 124,
Virtual9 = 125,
Virtual10 = 135,
Virtual11 = 136,
Virtual12 = 137,
Virtual13 = 138,
Virtual14 = 139,
Virtual15 = 140,
Virtual16 = 141,
Virtual17 = 149,
Virtual18 = 150,
Virtual19 = 151,
Virtual20 = 152,
Virtual21 = 153,
Virtual22 = 154,
Virtual23 = 155,
Virtual24 = 156,
Virtual25 = 157,
Virtual26 = 185,
Virtual27 = 186,
Virtual28 = 187,
Virtual29 = 188,
Virtual30 = 189,
Virtual31 = 190,
Virtual32 = 191,
Year = 88,
YearOnly = 35,
SortTitle = 163,
SortAlbum = 164,
SortAlbumArtist = 165,
SortArtist = 166,
SortComposer = 167,
Work = 168,
MovementName = 169,
MovementNo = 170,
MovementCount = 171,
ShowMovement = 172,
Language = 173,
OriginalArtist = 174,
OriginalYear = 175,
OriginalTitle = 177,
InstrumentsPerformers = 182
}