I've got a view-based NSTableView, using Cocoa Bindings to change the values of some labels and images in the cell. It all works great. However, I want to add a button to the cell. I've got the button working, but its action method only has the button as sender, which means I have no idea of the content of the cell that the button is in. Somehow I need to store some extra data on the button - at the very least the row index that the button is in. I subclassed NSButton and used my subclass in the cell, but Interface Builder doesn't know about the extra property so I can't bind to it. If I wanted to bind it in code, I don't know the name of the object or keypath that would be passed to it.
How can I get this to work?