The agent supposedly made the remarks in a radio interview while in Spain so I think it is fairly certain that he said them. The question is whether the remarks are reflective of what Vidic wants or whether it is a ploy to try and get a better contract from United.
I don't have any doubt that Pep would love to have Vidic on the team. It won't happen this year but it wouldn't surprise me to see Vidic in Barcelona in 2010/2011.