Laurens, thanks for such a rapid response. I wish that my corporate help desk was so fast with fixes!
I assume, from your response, that this is one of those small deviations from standards (i.e. to-the-letter, rather than de facto) that have cropped up over time. I had blogged about a
Blogspot feed problems with Microsoft tag that drove me to report a
Revisiting RSS reader choices inquiry. Since this new SunriseXP problem was cropping up on a Typepad blog, I guess it's not just issues with Blogger!