Swing Playback

Firstly, apologies if this issue has already been solved.

I posted a song which I wrote on the piano playing with a swing feel. Using the 'swing playback' feature it sounded OK on my computer but as we all know, the swing feel isn't saved, so when I uploaded it here it sounded completely different. I know this is primarily a site for notation but music is, after all, an aural experience, so I wanted the playback to be true to the way I wanted the song to be portrayed.
I discovered that if you save as a midi file it retains the swing playback.
I f you then load that into musescore it keeps the swing feel even when Play Panel option is set to straight. Unfortunately the notation then looks a bloody mess and pretty well unreadable from a playing point of view.
I have since discovered that you can 'tidy up' the notation back to its original look but the swing feel stays. You can then save this as a musescore file for upload and the swing stays while the notation remains readable.
How this works I have no idea, but I've tried it again on a much shorter snippet and it worked there too.

Here is the original upload with messy midi notation http://musescore.com/user/141397/scores/147272

Here is the readable version WITH swing http://musescore.com/user/141397/scores/156453

Straight snippet http://musescore.com/user/141397/scores/156464

Swung snippet http://musescore.com/user/141397/scores/156465

Hope this all makes sense.