Hi,
Exam 70-648 is already retired (since July 31, 2013) so upgrading from MCSA 2003 is no longer possible.
Have a look at the wiki I wrote about upgrading from MCSA/MCSE 2003, there is a section about what the options are if you can no longer upgrade because of exam retirement:
http://social.technet.microsoft.com/wiki/contents/articles/16483.upgrade-from-mcsamcse-2003-to-mcsa-server-2012.aspx
When you see answers and helpful posts, please click Vote As Helpful, Propose As Answer, and/or Mark As Answer
MCSE:Server Infrastructure, MCSE:Desktop Infrastructure, MCSA Server 2012, Citrix CCIA & CCEE, Cisco CCNA, VMware VCP 3/4/5 Twitter: @dnyvandam http://www.dannyvandam.net