Can iCloud's Documents and Data be configured to sync on a per-app basis? I'm considering buying DayOne, a journaling app for iOS and Mac that syncs through iCloud's Documents and Data feature. I already own the iWork app suite on iOS and Mac, and I do not want to use iCloud syncing for the iWork apps. Is there a way I can turn on the Documents and Data syncing on iCloud for use with DayOne without having the iWork apps sync through iCloud?

edit: Thanks for the iOS portion of the answer, Jonathan. I still would like an explicit answer about the iWork apps on my Mac, though. Has iWork '09 been updated for iCloud? If so, does each app have a setting to turn on/off iCloud storage? I read somewhere that there's a ~/Library/Mobile Documents folder where your files are stored if you are using iCloud, and I want to be sure that I do what is necessary to prevent the iWork apps from doing this once I enable Documents &amp; Settings on my Mac. Please reference the source of your information. I'd rather not have to learn by trial &amp; error. Has anyone already tried this?

edit 2: Sorry I didn't specify earlier, I thought it was an obvious assumption, but I'm using iOS version 5.1 on my iPhone and OS X Lion on my Mac (the latest released versions of both operating systems).
You can disable iCloud on iWork by going to the Settings app, and scroll down to the install apps settings, you will find each iWork app has it's own section, Pages, Numbers and Keynote.

In each iWork app's settings there is an option "Use iCloud". Turn this to off, and keep the Documents and Data in the iCloud menu on.

For Mac, the iWork apps do not support iCloud Document Sync. (If you enable sync on iOS, the files created on iOS will download into your library, you can't open them however, and you are unable to upload to iCloud in iWork)

In Mountain Lion they will, but it appears that iCloud Doc sync integration will be at the OS Level, rather than iWork app level. Instead being more like DropBox* where you have an area (I say area, because it's not a folder, but it's quite similar to one) for iCloud.

*Although this area only seems to appear in Open/Save Dialogs, and will only show files that are registered to the App.