Opening with external editor always makes new version

i am a fine art figure photographer and portrait artist. almost every photo that i want to finish has to be round tripped to photoshop for retouching. in Aperture 1.5, i could select a photo, open in external editor (photoshop cs3), make my retouches and save the new version. if i wanted to re-visit the image and make further modifications, i could select the round-tripped photo, open with external editor, and the edited photo would be opened without creating a new version.
now in Aperture 2.0, once an image is edited and the new version saved, if i try to re-visit the image Aperture always creates a new version. this is a behavior that i don't want. new versions of photoshop edits are expensive when it comes to disk space. and with 30,000 images in my library, i just can't afford it!
in the preferences, i have the option "Create new versions when making adjustments" unchecked. that's the only option i can see that affects the automatic creation of new versions. any advice on how to edit the image without making a copy would be greatly appreciated!
Message was edited by: scott nichol


I had the same problem as the OP and was surprised to read that Ian didn't encounter that same behavior. So I started testing several options. This is what I found;
When I open a previously-externally-edited picture from within Aperture, using the keyboard shortcut ⇧⌘ O, Aperture automatically creates a new version.
The same thing happens when I choose 'Edit with Adobe Photoshop CS3' from the Images menu in the menu bar.
On the other hand, when I open a previously-externally-edited picture from within Aperture by Ctrl clicking the picture and choosing 'Edit with Adobe Photoshop CS3' from the pop-up menu, the picture opens in Photoshop without Aperture creating a new version first.
Very strange because the pop-up menu command has the same keyboard shortcut as the commands I used in the first and second attempt.
Hope this helps.