Paradise Within

We discussed briefly at the end of class that Milton believed in a "paradise within." We speculated that perhaps the fall was not a loss of heaven but rather a change in the method of attainment. When Milton writes "Paradise Regained" he asserts that humans can reach paradise without being allowed back into the Garden of Eden. Ok, so this all seems logical, the discrepancy I have found is in Satan's support of "paradise within" but his inability to find it even as a "heavenly" being. Satan belittles his condemnation to Hell by theorizing that "The mind is its own place, and in it self / Can make a Heav'n of Hell, a Hell of Heav'n" (254-55). This seems to support Milton's belief because Satan thinks that with a positive attitude, he can find heaven in hell. We see Satan struggle for the rest of the poem with his inability to be happy or content; he mellows as he watches Adam and Eve but is overcome with anger shortly thereafter. He consistently laments his hubris and wishes he had never fallen from heaven. His emotional distress implies that he has not found heaven in hell. Does provide evidence against Milton's belief in a "paradise within"? Is this an inherent contradiction in Milton's argument or must we define "heaven" by different standards?