[Samba] How to remove ability to delete files

[Mike Gallamore]

Hi, this is kind of a strange situation. I have a share that I want to  
work like a drop box. I want users to be able to create new files and  
read existing files, but not be able to delete them (except for the  
owner of the dropbox). Does anyone know how to do this?

I've tried every combination I could think of write list, read only,  
force group, and sticky bits on the directory itself. Any help would  
be greatly appreciated.