Embedding a TreeView control in a node

First, GoDiagram is a great product. Thanks for making it. ( =
Second, I want to embed a TreeView into a node so that every element in the tree, including the root, have ports coming in and going out. This sounds suspiciously like the MultiTextNode, it’s true… but I want the branches to be expandable and dynamic. I’ve seen some posts about using GoControls, but I can’t quite figure it out… and the Demo1 project is specifically creating the RichText control as an editor.
I’m hoping that I can subclass the TreeView control in System.Windows.Forms somehow… but I’m starting to think that I have to subclass MultiTextNode and draw the branch lines myself, and detect mouse clicks by the user… any ideas besides these?