I was just posting my own thread about this, but I guess one is enough ;)
http://www.boardgamegeek.com/article/13222683#13222683
(reference to BGG-thread)
My take is that he cannot; he "does not have the melee skill, and there is no weapon played that could add the melee trait, otherwise he could not replace the die. It is a dexterity combat check with no further traits (assuming the power is not upgraded and no further cards are played). Melee does not mean "any attack that is not ranged", it is a specific keyword added to the attack." (quoted myself from the thread)
While I feel confident in this assessment, I wanted to ask for official clarification to make sure that that is the intent.