I'm unaware of any DW CS6 plug-in that can do this for you 'as yet'.
How about filing a feature request with Adobe to see if they can implement it into DW directly?!
I'm going to reply to myself, just to let anyone else who needs to create an RSS Feed know that I did find a solution to this issue - but it is using a standalone product called FeedforAll.
FeedForAll works under Windows 8 (in compatibility mode). I downloaded an eval version from the FeedForAll website, and was able to duplicate my existing feed (which was created using RSS Dreamfeeder, a now-obsolete extension to Dreamweaver CS4) in roughly one hour's time.
You can view my original feed, using the link from my original post above. Here is the test feed I created today using FeedForAll:
As Sudarshan suggested in his reply above, I did put in a feature request for Dreamweaver using the link he gave me - so hopefully Adobe will eventually add in this as a new feature ... because many of us website developers do need to create customized RSS feeds, and it would be great to be able to do it all from within one development environment, Dreamweaver.