Hi Danzig,
My graduate school told me that the date that appears on your pass list is the date you are formally awarded the PhD, not the date of your graduation. So for me I passed the viva early november, appeared on pass list late november, graduated december. On my CV I put PhD awarded november 2009.
If you haven't already been sent a copy of your passlist (or a letter confirming you have passed) I would ask at your graduate school/admin office.