I’ve created a comments feed in Atom 0.3 format. You can visit my site for more info, including the source code download and some integration information.
Spectacular. OK, here’s the Unicode: #8482
When you want to use it, surround it with & and ;
If you read the feed validation page and click on “help” next to the error involving the date you’ll see that it is indeed the localization of the day that’s causing the problem. The only allowed possibilities are Sun, Mon, Tue, Wed, Thu, Fri, Sat.
As for the trademark symbol, you might try using the Unicode markup instead of ™. The Unicode is: ™ (according to http://www.natural-innovations.com/wa/doc-charset.html, although it also lists ™). I supposed it’s possible to modify your original post to change it to the Unicode.
