File Sharing Help — Create a viewable drop box?

Hello.

I've been trying to set up a viewable drop box, and I've had nothing but headaches, so I'm hoping someone could give me a hand? I'm just looking for a drop box that people can write files to, but also have the ability to view the files they've placed in the folder (that's where it deviates from the standard drop box). Here's the details I've what I've been doing:

I have two users — USER-A and USER-B.

I have a Share Point called FILES, which is READ ONLY for both users.

Within the FILES Share Point, I have a single folder called DROPBOX.

On DROPBOX, I want USER-A to be able to read, write and delete (the contents of the folder)—this is standard Read & Write ACL. I then want USER-B to be able to read, write but NOT delete (the folder or it's contents)—this is a custom ACL.

I've tried setting the custom ACL on that folder so USER-B can read and write (but unchecked the "Delete Subfolder and Files" under Write), but this isn't working. As soon as I uncheck "Delete Subfolder and Files", the user can no longer write to the folder?

So, I'm wondering if someone could advice me on what I might be doing wrong?

Thanks,

Kristin.