How can you instruct on the instrument portion of handling a multi-engine plane while operating under IFR? If I recall the instrument rating has a single and multi engine options. If so then my guess is that the training needs to come from an MEI. Besides all that how would you the instructor log the time? As instruction given? Most likely the only way to legally log the time would be as a safety pilot. Perhaps you could provide instruction in a multi-engine however the check ride should be in a single with a limitation for IFR in a single engine planes only.

SkyHigh