Creating Geometry in Autocad for COMSOL - 3dface - surface problem

I have a very complex geometry to be analyzed in COMSOL that can best be modeled by Autocad using 3Dfaces. After composing the model in faces I used the converttosurface command in Autocad, this is how COMSOL could open a visible model (by LiveLinktoAutocad). However all the boundaries (thousands of them) have this warning: not applicable in parenthesis. On the other hand, all the edges, points in connections and all drawn boundaries can be seen in Comsol graphics. Is there a way to build a solid model in COMSOL out of this so called- not applicable- surfaces, or is there a way to convert those boundaries to applicable ones.

Thanks