I had the problem of saving files which I uploaded programatically to Sharepoint list item. When I tried to save them, there's pop up dialog saying the file is in read only mode, even I had all the required permissions. There's not much info on the net about this, and luckily I found the solution.
Because I had decided to use my own edit/ display form, which contains the attachment links, there's one attributer I missed which is required for Sharepoint to hook up with Microsoft Office in order for the synch to work.
For the attachment links, just remember to put the following onClick event in and everything will work perfectly:
"DispDocItemEx(this, 'FALSE', 'FALSE', 'FALSE', 'SharePoint.OpenDocuments.3')"
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