Audiobook won't shuffle on ipod nano (and other related issues)

Question

I am learning German and I bought a set which comes with an audio companion that you can use on your MP3/ipod.  They come in units of no more than 3 minutes each and there are quite a few of them.  I uploaded the content onto iTunes.
First of all iTunes recognised them as music and displayed them in my music file.  No big deal, I went to 'Get info' on each one and changed the media kind to Audiobook so that they would show up there and not play with the rest of my music.
This is where the problems start: -
1.  For some reason my nano won't shuffle the units.  I can only assume that it thinks these are 'books' which you wouldn't shuffle.  As such it simply plays one unit (3 mins long) and then repeats it.  It doesn't even move onto the next unit/book.  I've tried turning shuffle on and off, both on the ipod and on itunes to no avail.  I've gone into 'get data' and the tick-box which says 'Skip when shuffling' is greyed out and can't be unchecked.
2.  I can't skip to the next unit like I would when listening to a song.  Pressing forward (right) does nothing.  I literally have to return to the main menu and select another unit manually.  Oddly enough, the only way I can get round this is by going into settings on the ipod and turning shuffle OFF.  Then it allows me to skip to the next unit!  Problem being that then none of my music will shuffle.
3.  Once I select a new unit (either my returning to the main menu or skipping forward by turning shuffle OFF) it remembers my last position.  I'm sure this is great for books, but not these small 3-minute units.  I've gone into 'get data' and the tick-box which says 'Remember playback position' is greyed out and can't be unchecked.
These are my problems.  I just want them to be like songs, but in a different file (i.e. not music) where I can skip forwards and backwards.  I've tried adding them to their own playlist but the problems remain the same.
Any suggestions as to why this is or how I can resolve it would be greatly appreciated.  It shouldn't be this hard.

Answer 1

Update to this -
I just tried changing it all back to Music, checking ''Skip when shuffling' and adding them to their own Playlist.
This works in so far as they won't now play when my music is playing, but I still have to turn Shuffle OFF in order to be able to skip units!
I want these shuffled, but of course I can't uncheck skip when shuffling, otherwise they'll play as part of my music.  Catch 22.