generally you put an Outlet in YourDocumentType to the controller.
the generic controller keeps an instance var named "contentObject", which you can access by name:
[myControllerobj contentObject]; (big part of KVC btw)
what should follow in your brain is all of the cards falling into place for how to connect to any other data In any other objects in the controller layer.
simply look it up in the new online Apple dev ref docs, and find the name of the offending data, then make "yourclass" aware of the controller in IB, and you can ask for any of its data.