I think that's only a challenge at all because of how mass and power limited such a craft would be. The obvious solution is to use lasers.

It might even be possible to use a modulated retroreflector on the craft-- e.g. we fire a high power low divergence beam at the craft and it reflect it back. By modulating the reflection in can send back data with practically no power usage.

The angles accepted by the reflector could be fairly hard and so the difficult pointing problem would only exist on our end.