Here my Mail that didn't make it to you:

"
Looks like the old code deleted *all* properties of a FileClass (which
happens to match for messages, too). My new code only checks the case
that the content is empty and removes an empty content property. So
re-adding
>   -                if id is not None and id.startswith('-'):
>   -                        del all_props[(cn, id)]
probably should do the trick, I have no time to test this now, though.
So I would change the existing code to:
                # Avoid emptying the file
                if props.has_key('content') and not props['content']:
                    del props ['content']
                    if id is not None and id.startswith('-'):
                        del all_props[(cn, id)]

The problem I was fixing is that an item-template for "file" did no
longer work for me. The changes above will not create a file/msg with an
empty content in case some other properties are filled in but *will*
allow changing properties for an already-existing file or message.

But not tested :-)
Let me know if you have time to test this, or if I should look into this
"

I've now committed this change (after verifying all tests pass).
Please check if this fixes your problem and maybe you can add a test for
this.

Thanks
Ralf