So... I've also been researching creating custom skins. So far I haven't had any real luck with that. InstallShield X (IS-X) ships with a handful of predefined skins. There is NO mechanism for discovery of new skins in IS-X. If you want to create a new skin, you actually have to manually alter one of the existing ready-made ones.
There are a load of problems with the support for custom skins in IS-X. The biggest problem is that there ISN'T ANY SUPPORT! People who rely on the “community” for answers can forget about it. Sadly, people actually willing to pay for support aren't much better off. There are COUNTLESS messages on the “community” about people being told “it's trial and error” when creating custom skins. Things like proprietary “dialog units” that have no real world correllation to pixels, and getting your images or buttons to show up in the right place... TRIAL AND ERROR? That's the official response? Seriously??
There have been many times I have considered asking my employer about purchasing a support contract so I could get some serious help when I need it (been doing pretty good without it though, thankyouverymuch) but after seeing this... I don't think I'm willing to waste the money.
Trial and error.... yeesh...