using reference sketches in Softimage 7.5 ModTool

I have a very noobish question that I've been wondering for a long time. I'm using reference sketches/orthogonals to guide me in character modeling in Autodesk Softimage 7.5 ModTool. I've placed these sketches onto grids at right angles to each other behind the area where I'm modeling. How can I set the display preferences or object properties so that I can see through the polygon meshes in textured decal mode (which is required to see the jpeg images that I'm using as guides on the grids)? I've set display options to x-ray mode with screen as the x-ray type, but this only allows me to see through to the other side of a given mesh, not through the mesh to the reference sketches behind it.

I'm sure there is a setting I'm overlooking but would appreciate a nudge in the right direction.