use ccx, custom model definition. define minimum properties in Mecway; there are some missing "don't generate" commands, for example you can't "don't generate" *EXPANSION, so only define these in the CCX custom file see example
The "don't generate" commands suppress any material commands you have already defined in mecway, since you will be redefining in custom model input. So define the bare minimum just so that mecway doesn't complain, then suppress whatever you have created.
Comments
define minimum properties in Mecway; there are some missing "don't generate" commands, for example you can't "don't generate" *EXPANSION, so only define these in the CCX custom file
see example