external flow meshing for a Sedan in pro*am

rave

I'm stuck.

I want to create volume mesh around a sedan geometry for external flow analysis. I tried pro-am for tht but I always endup with an internal mesh.

I even tried inverting the cell orientation and creating subsurface outside the original geometry, but after tht i don't know how can i input the extent of mesh creation outside the car-body.

also in the manual its given tht for external flow analysis a box has to be created outside the geometry, which wd create flow volume outside the body(external flow).Can sm1 tell me how can i attach the symmetry plane of the car with one of the faces of the box so tht external flow mesh cd be generated.

i wd be very thankful for any help.