if you are not affraid of take the risk , read this post, I did a P28 from auto to manual once , but it's a different procedure on yours I guess, if the ecu on this thread is not the one you have, try to google it.
Honda-Tech.com: Honda Prelude: The official auto to manual ECU conversion thread
Honda-Tech.com: Honda Prelude: The official auto to manual ECU conversion thread