I've seen lots of posts about switching between Beta patch versions and the amount of work some are going through to switch them.
You can use JoneSoft Generic Mod Enabler to switch between these and back to stock.
Go here to get it;
http://www.users.on.net/~jscones/sof...cts-jsgme.html
Install it to your Steam\Steamapps\common\il-2 Sturmovik cliffs of dover folder, run it, then extract the patches to the MODS folder in there.
Run it again to select which Patches you wish to install/uninstall.
It's been working fine for me.
Cdr