Save as 3D dxf

Hi,

I'm currently running Solidworks 2012.  A customer has asked me for a 3D DXF file.  I had previously sent him a .stp file but he said they could not open it.  Is there any way I can do this in Solidworks or maybe through a medium as Inventor? If not, is there a different way I can do this?

Thanks

SolidworksImport export