Please don't generalize about the iPad. What the iPad can and cannot do depends on what app(s) you are using. If you are talking about iBooks, then say so. Don't just think iBooks is the iPad. It's not. iBooks is just an app. It's not the iPad and never will be.
That said, iBooks can indeed handle embedded fonts. But you have to do something non-standard to the ePub to get iBooks to turn on embedded fonts.
Take the attached file and put it inside the META-INF directory inside the ePub and your embedded fonts will work with iBooks.