Documentation Build date

I want to put the documentation build date in every DB template so it is there for all DB projects. In DocumentX 2008 I set up a template property with a value of %%longdate%% In DocumentX 2011 I can create a property but can't find anywhere to specify its default value. I'm quite surprised that it isn't a standard part of the documentation in any case. I'd really appreciate a walk through of how to get the build date incorporated into a DB template.