For blog 1: While submitting sitemap to Google webmaster tool I selected the option and then added rss.xml at last. (http://name.blogspot.com/rss.xml)
Sitemap added successfully.
For blog 2: I followed the same procedure but it didn't work.
Then I tried to open the url (http://name.blogspot.com/rss.xml). The url was showing the atom feeds.
I tried same with the other blog but that url is redirecting to the feedburner feeds.
I think this is the reason why the other blog's sitemap is not getting submitted.
Help me with it.