Color mapping NX to autocad

[hashso25]

Hi,
Im trying to generate a dwg file through Autocad DXFDWG translation, the input for which is a CGM file.While exporting the CGM file from a part file i select options Export CGM->Properties->Colors->Black on white . The thing is even though the geometry appears black in NX it shows brown color in Autocad DWG file. How do i get the same color in Autocad.Is there any color mapping file or do i need to do anything else.Im using NX9.

Thanks in advance