In repairing a steel wall rust hole (with a patch) is the object to prevent the liner from protruding out the wall or is the patch supposed to strengthen the area ? A friend suggested a vinyl patch . Either way I would be wire brushing all rust off fill with epoxy then use rustoleum paint and last put a patch vinyl or metal so no further water can attack the area.
http://s1226.photobucket.com/user/Fatchoppers01/media/tama/pool pic_zpsocfdfd4j.jpg.html
http://s1226.photobucket.com/user/Fatchoppers01/media/tama/pool pic_zpsocfdfd4j.jpg.html