Admin order page, custom field

[crustydod]

Hi,

So, now that PS is so more optimized code wise and overrides don't work anymore, please point me in the direction on how would one add a custom field with a button to an order admin page?

Let's say I wanted to add a new field under Documents tab on the page of the order. Or anywhere else.. And of course I want to save that data when the button is clicked.

Hooks? Yes! AdminOrdersController.php doesn't really have what one would need right? Or am I missing it?

PS version: latest at the time of this post.