The viewport shadows depend on the settings used in the native c4d lights.(none, shadow maps, hard and area)
It should be possible to emulate those settings in coming versions but currently, it's not possible. What you could do is to place c4d lights at the same spots as the corona lights and make them only visible in the viewport.(coords. tab->select all, copy&paste)
Edit: You could, of course, use the native lights, but that's a similar thing as using the native materials and you'll eventually run into some limitations.
However, the light's noise function(projected) seems to be working fine.