Transparency of masked reference

I have a file with several filled associative regions with the transparency of the fill set to 60%.  I reference this file into a container file where I mask out portions of some of the associative regions.  I mask the reference file using fences created from elements.  Once I apply the mask to the reference the transparency of the specific masked region changes and is no longer the same transparency as the "non-masked" regions.  Is there a setting somewhere to fix this so that the transparency does not change when the reference is masked?

I have my preferences set to "optimized fence clipping".

MS 08.11.09.608

TIA