A method of making an interior trim panel for attachment to structure of a vehicle includes the steps of loading a trim blank into a cavity of a mold and loading an edge of the trim blank on a movable slide of the mold. The system can include a first liquid composition and a second liquid composition. In a preferred embodiment of the invention a self-synchronization is provided for synchronizing a sampling of the output voltages of detecting circuits relative to the occurrence of a signal on the transmission path. Latch assemblies can be selectively actuated to secure the wing brackets and associated wings to the truss in either the deployed configuration or the retracted configuration, so that loads between the wings and the truss are primarily carried through the latch assemblies rather than through the hinge assemblies.