Permissions per content-type and user

I have a system with some users, as usual one admin which manages every content types and other roles. A publisher, a specific role in my system, which is not admin but manages only certain content type. I seek for a module with these features but I could't find it, but I found this module with a amazing interface so I modified some code in the nodeadmin.module in order to manage permissions over the content types.

Then, I have some problems when I try to create, edit or delete content, because the submit button has no effect, and I don't know why. So I modified the lines to hide the create content section from the form and to modify the links to the usual operation pages (node/X, node/X/edit, node/X/delete).

Furthemore, I insert some t() functions to make translation easier. :)