I sent you an email yesterday with what we believe to be the solution to the problem. Let me know if this solution helps you in displaying the cells in cross sections.
We believe the limitation for the display of a cell in a cross section is the cell must be in the attached cell library. it cannot be a shared cell or a cell called up from a library in the MS_CELLLIST. So you need to make sure you go to Element > Cells, toggle off the options for "Use Shared Cells" and "Display all Cells in Path" then make sure you Attach the Cell Library to see what cells you can use for displaying in the cross sections.