Hi Bruce
You can 'wing' it using the "Pre-cast slab builder" accessory under CADImage libraries (for those who have the CADImage tools).
First draw the slab extent, then select it and choose "Slab accessories" under Design->Design Extras. Choose the "Pre cast" accessory - in the test I have done I used the Double T section with custom settings (600 wide by 60mm deep, 5mm thick section) - see attached screen shot.
At a guess we could ask CADImage to add steel tray profiles to the accessory tool.