Go here http://www.dmac.org.uk/

and click on downloads, Agree to the legal stuff, click on #10 called Flying Aerobatics. Download it and install it. It describes both maneuvers you are asking about and more. Once installed it will open in your broswer and the maneuvers are at the top and once you click on it then you are presented with a great explanation and diagram. The illman is acutally spelled Immelmann

Get all of the others also, this is some nice stuff. Although not mine, they are good