FWIW I've been investigating this myself.
iWork doesn't actually work from a WebDAV server. It is simply able to copy things over from one. Any docs copied over then live in iCloud. So updates don't appear on the WebDAV server.
The dream of seamless interoperability with Macs is still a dream until better iCloud integration happens, presumably with Pages 12 and Mountain Lion. This is a shame.![]()
While you're correct that once downloaded the documents don't automatically updated back to the WebDav server, you are able to copy them back up to the server and overwrite the original. So, it's not seamless but it is possible
Ah! I didn't realise this and did look hard. Can you explain how?
Go to the view where you are looking at thumbnails of all your documents. Tap "edit" in the top right corner. Select document(s) you want to copy to WebDav. Tap arrow icon in top left corner. You'll now see several options for sharing the file(s), one of which is copy to WebDav.