A conceptual design for a heavy ion beam probe diagnostic for the stellarator WEGA in Greifswald (Germany) is developed to provide measurements of the radial profiles of the electric plasma potential, density, and their fluctuations. Calculations of probing Na+ beam trajectories were done for the various WEGA diagnostics ports with B0 from 0.087 to 0.5 T. They show that satisfactory access may be possible for C+ C- port combinations.