Is it possible to make DirectX generate a index buffer from a vertex buffer automaticly?

The problem there would be that the pipeline would not know what to make of the vertices in the vertex buffer with respect to topology.

You''ll have to create your index buffer independently im afraid

Maybe more explanation of why you would want the index buffer to generate the indices automatically (aside from any convenience based justifications), would probably help us understand your problem.

Regards
Kraik