You can upgrade to MCSE:Server infrastructure from several MCITPs and from the MCSA:Windows Server 2008, but not from a plain MCTS. Unfortunately, if all the exams that you have passed are only the ones that you mentioned, then you don't have any of the
required certs. Therefore, in order to achieve the MCSE:Server infrastructure you will have to pass all five required exams, as listed in the certification page: