Hmm.. weird, I don't have this problem. currently have 3-12-2008 selected, and it starts with W for Woensdag.
Are you running on an english version of XP or something?? mine is Dutch unfortunately, but that might just be the difference

Your screenshot also says Today: 03-Dec-08
Mine says Vandaag: 3-12-2008
might be a small glitch in the date processing of the Source application