User cannot move email messages within Outlook Inbox folder and sub-folders.


Hello,
I am having issues with an Outlook user within our exchange environment.
We are using Outlook 2003 & Exchange 2010.
Currently the user has access to a shared exchange mailbox.
The original requirements are that the user requires modify access but not delete.
I have added the user to the Mailbox and all subsequent subfolders.
This all works fine.
Now I have had a second additional request asking if the same user can ALSO move mail between Inbox folders and subfolders.
This i cant do.
If this is a know issue or limitation when applying the NO DELETE permission, that's fine.
But I cannot find and reference to this.
Can someone please assist or point me to the correct reference URL?
Thanks,
Darsss.