[Therion] loch with 2 surfaces

hi all, i tried to create a model with two "surfaces": --------------------------------------------------- source all.th source surface cs UTM32 input surface1.dem endsurface surface cs UTM32 input surface2.dem endsurface endsource export model -fmt loch -o cave.lox export model -fmt dxf -o cave.dxf ------------------------------------------------------ in dxf i got both surfaces, in loch only the first. any reason why ? thanks, marco