We have several assemblies containing very large sheet metal parts (12 gauge with very large size) where some parts are "mirror" (reversed geometry) of other parts.  When simulation generate the mesh those parts are recognized as solids not as sheet metal parts and Simulation do not mesh them as surfaces (shell), the 2009 version of simulation do not allow the user to control the type of mesh (or at least we have not found how to control it) therefore the analysis takes for ever... any ideas or solutions?