Help with Wire Form

Hi guys, I already extended the wire form to add a couple of things. I'm having problems with a dropdown box. I want to save what the user select in the dropdown box, but I don't know why it is not being save.

Here's the add.php (The Wire form extended)


And the action extended (add.php)


P.S. I want this to work like the 'categories' which are save with the wire post, but don't show up in the wire (but the wire post shows when you search the category)