How do I set an Edge-Flange's angle using global variables in SolidWorks 2012?

Hello,

I am trying for the first time to create a part using global variables.  How can I use a global variable to set the angle of an edge-flange?  I am, for whatever reason, unable to select a face to make the edge-flange's angle either parallel or perpendicular to, so this seems like the best option. 

Thanks for your help!

Travis

SolidworksParts And Features