Convert .dat .pak .fsb (.xen) files without dlc containers

[bembee]

So Onyx successfully open (and convert) Guitar Hero 3 dlc files (xbox 360). These dlc files contain 3 assets.
music.dat.xen
music_song.pak.xen (contain chart files)
music.fsb.xen (contain xma files)

Is there any way to open these types of files (dat.xen, song.pak.xen, fsb.xen) without the xbox 360 dlc container?
I mean is there any option to locate these 3 files to Onyx to convert it?
For example to convert not dlc (files) song, but the original GH3 songs (dat.xen, song.pak.xen, fsb.xen files).