Changing rotation axis in assembly

Looking to rotate a part within an assembly around an axis of another part within the assembly.  The end goal is to determine a hole angle based on the desired position of the tube.  When I rotate with the triad the rotation axis is not the same as the axis of the part I need to rotate on.  I have attached a picture to better define what I mean.  The axis I want to rotate around (the case axis) is the red circle while the blue circle shows the triad rotation axis (the tube axis).  

SolidworksAssemblies