Check out the following article - I think it might describe how to go about creating the view you're looking for:
Feel free to reply if you have any questions!
Unfortunately this doesn't help me - it just gives me an extra legend with a circle (or any other shape)... I would like to distinguish between the two in one legend.
Gotcha! Based on what I can find and the testing I did of my own, this seems like an enhancement request (Ideas ).
With that said, I'd still be curious to see if anyone else has any ideas on how to accomplish the desired legend view.