John
Have a look at URGalaxy on Ebay – I recently bought a 1.4 Kenko converter (DG300 from memory) and it works with all lenses, and allows AF. Much cheaper than the Canon couterpart (smaller as well) and the Canon only works with certain lenses.
The answer to that is probably it doesn’t. Olympus has its own lens fitment I presume, and I certainly have not heard of an Olympus fit for this kind of thing.