First of all, you can have the hands on experience. Try Technet Virtual Labs. This will give you enough experience to understand and pass virtual labs in the exam. Like Alberto noted, that was only a suggestion. So go on and pursue your 70-642. One
advice though - at the same time prepare for 70-640, this will greatly increase your chances on both.
Besides, your attitude towards the exam is great, as I know for sure there is a whole country in the world (but I am not racist, so won't name it), where MCITPs haven't seen Windows Server 2008 until the exam.