I havn't looked at the shader to see if there is an editable, or locked-out transparency node,
but try making a layered shader with:
-a basic Blinn on the bottom containing your ramp transparency,
-then add the diffraction
shader on top of that at about 80% opacity with a blend mode of ADD.
(or try them all to see what might work best for a blend mode
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS