Alleged Bin Laden Tape

Some large Italian media are reporting without qualification that the man in the alleged new Bin Laden tape is not the real Bin Laden ("Non è il vero Osama" is what RAI 2 said and scrolled across the bottom of their news cast; RAI 2 is equivalent to an ABC, NBC, CBS or CNN). Although the picture in the video is somewhat distant, it sure doesn't look like the real Bin Laden should look like, especially the beard. A quick check of CNN, NYT, WaPo, HuffPo, Informed Comment... seems to suggest that they all think it's really him, or at least the voice seems to belong to him (this last assertion based on initial testing according to some unidentified American official(s), whom some Itlalian outlets, as well as Al Jazeera, are also quoting). Am I missing something? Are there any American sources saying it's not him or may not be him? Are there any other authoritative opinions besides anonymous American government officials in the world? This seems to me to be a pretty significant difference in reporting that is rather hard to explain.