[Zope] ViewAndCopyOnly role

[Bill Kerr]

how should I set a role for users of a folder where they can view and copy
files only?
I've set these permissions:
View Management Screen (for seeing the files)
Access Contents Info, View (for rendering the files)
Add Doc, Images, Files (for copying the files)

This almost works but the problem is that with Add Doc, Images, Files (which
I need for copying) the users can also add things to this folder and I don't
want them to be able to do this. I think I want a permission that allows
copying but not adding.
- Bill