You all have to realize Pasi S. is in Finland , no Autozones ,lol . I would try using Permatex non-hardening gasket sealer especially where rips (cuts) are . I think making a gasket would be last choice . It's not impossible , but it's a pains taking job , I've done it. Second choice would be RVT (silicon) , nice bead, let set little bit , set cover on ,start screws , but dont tighten , let set couple hours , then snug screws. Then when you get new gasket replace it. If this has to go through a translation program I hope you understand it . Let us know how it turns out.