I'm still a little unclear on the class hierarchy. It sounds as if it is either: NSView : "BlackBoxViewClass" : "YourViewClass", or NSView : BlackBoxViewClass. (If it is the latter case, I'm not sure how you are changing the role - are you using a category)?
Since the parameterized attributes are already fully implemented on this "black box" class, it also makes me a little suspicious that perhaps there is an NSTextView, NSTextField, or NSTextFieldCell involved somewhere - perhaps unbeknownst to you, but regardless.
If the parameterized attributes are already working in your superclass, I believe you can get this to work by adding attributes to the attributed string you return from the AXAttributedStringForRange parameterized attribute.
The attribute is NSAccessibilityLinkTextAttribute, and the value of the attribute should be the appropriate child element that you already have created. The attribute should be added to the range of text that has the link.
So, either you will need to override AXAttributedStringForRange, take the outgoing attributed and add the attribute and link element to the appropriate range, or if you can't override, you will reimplement that parameterized attribute to do the same thing.
You will also want to update AXRTFForRange to do the same thing.
Usually NSTextArea takes the link and does this, but in this case you will need to do this manually. I haven't tested this approach myself, please let us know if it works for you.
-James
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James Dempsey
AppKit Engineering
Apple