Problems getting data from Garmin 310XT into RaceDay

I have my data downloaded from my 310XT to Garmin Training Center (and Garmin Connect). And, I see that I can export my History (.tcx file) from Training Center to my computer. However, from what I can tell, I need files for individual workouts to be able to import them into RaceDay. So, how do I do this? Are these individual workout files stored somewhere on my hard drive? If so, where? (I’ve looked and looked…) What’s the file extension?

I’m running Vista, BTW.

Steve