Make your own weapons????

Im trying to make up some of my own weapons in cfs2. Ive got fsds pro and can make .bgl files to get the shape of the bomb and place it in scenerydp/ weapons/ scenery. Then use an object .dp file from another weapon i.e a Torpedo and rename it and put it in the objectsDP file. Then i change an Aircrafts .dp file so that the bomb shows up in the weapons list. I then update the aircraft .mdl file with an .mdl patch. However once i start cfs2 and look up the aircraft it tells me the bomb is not in the library it also tells me that all the other weapons are missing on all the other aircraft. What am i doing wrong??? can u help..are there any tutorials on this kind of stuff?
cheers Ian.
cheers Ian.
