[MacRuby-devel] What's the best way to implement a delegate/action with multiple parameters?

I'm pretty new to Cocoa, so maybe I'm overlooking the obvious here. I just want to make sure I'm not doing more work than necessary. I'd like to be able to control the minimum size for a NSSplitView. As I understand it, I need to have a delegate with a method that can handle splitView:constrainMaxCoordinate:ofSubviewAt: So far that isn't supported using Interface Builder, is it? If I need to do it 'manually' - do I get a reference to the NSSplitView, and then tell it to set its delegate to something that responds to the method? When/where should I do this - in the Window Controller's AwakeFromNib or some other place?