Because the custom channels are fakesigned you need to use a WAD installer which supports fakesigned WADs i.e. not wadImport. This means there is no WiiBrew supported way to install custom channels. However, it would apparently not be too hard to make one with the necessary checks in place to prevent use in warez. Of course, when I say "not too hard" I mean for an experienced programmer used to the Wii, not someone like myself ;)
