Why is iBooks Author using up my scratch disk space?

I have recently created a graphic rich travel publication in iBooks Author on my MacBook Pro 2.4GH laptop. When I started I had 50GB of space available on my hard drive. Two days later I received a warning from iBA that I was running low on disk space. Amazed I checked and found that I had less then 2GB remaining. I wrote to Apple 3 times askaing their advice, and have not even received an acknowledgement.

Eventually my recouse was to back off all the files on my scratch disk, completely reinitialise it and reinstall OSX Lion. My thought were that perhaps someting remained in my system from the old OSX 10.6 that was interefring and causing the problems. A clean install would solve it. I started working once again on the newlt installed system, this time making sure I kept track of the space available at start and finish.

At kick-off I had 157.45GB of spare space, and I then made a few changes to my iBA source file. I rechecked the space available afterwrds and, low and behold. it had fallen 147.29GB. iBA had placed another file on my desktop postscripted with a hyphen. I drop this in the bin, emptied it and rebooted the Mac. On reboot there were a couple of recovered filed folder in the bin, totalling 320MB. I deleted these and rechecked the storage space available. It was 147.8GB an increase equal to the disposale of the duplicate source file plus the recovered items file, but still nearly10GB lesss than when I started.

So where did nearly 10GB of space go?

Well, it seems to me that iBA uses a similar method as Time Machine to save changes to the file so that it is possible to back-track. All well and good, but at least with Time Machine there is the option to switch it off. With iBA there is no such option, and it appears that iBA, instead of saving just the changes made, saves multiple complete copies of the file nd does this using an auto-save facility which also cannot be switched off. Furthermore the save file, unlike a Time Machine file appeares to be a 'hidden file' which cannot manually deleted. The only way it apperas to get the disk space back, is to once again, back up all the files of your hard drive, reinitialse it and reinstall the system. Pretty inconvenient!

Unless, of course, someone knows why this is happening and how I can get my disk space back without having to go to this extreme. My source file is now finished and ready for upload, so won't get any bigger, but the finale count is that my disk space is now down to 137.47GB, which means that iBA has now eaten 20GB of my storage.

I checked with another iBA user and she informs me that she had exactly the same problem, so it's just not some abberation of software clash specifically in my laptop. iBA is a nice applicatio to use, but not if every time I use it I end up havig to erase and restore my laptop.

It also doesn't help that Apple have not responded to three emails have sent them either.

ANY IDEAS ANYONE?