"double-sided" raycasting

I want to have not just the contact point for a raycast with a specific shape, but also the point where the ray would be leaving the shape on the other side. I don’t care about any other hits, just the first shape along the way, but an “entering” and a “leaving” point. What should I do?

I used raycastMultiple and set the flags eMESH_MULTIPLE and eMESH_BOTH_SIDES, but it doesn’t do anything: I only get the initial hit-positions, no points on the back-side. I guess it’s not meant for simple geometry-shapes, like boxes in this case. Isn’t there some kind of “local raycast against geometry” function, so I can manually raycast from the other side without fear of any other shapes getting in the way, or having to adjust all the query filter data just to avoid this?