pubDate format error

As per RSS 2.0 pubDate should follow RFC 822 as follows:

pubDate The publication date for the content in the channel. For example, the New York Times publishes on a daily basis, the publication date flips once every 24 hours. That's when the pubDate of the channel changes. All date-times in RSS conform to the Date and Time Specification of RFC 822, with the exception that the year may be expressed with two characters or four characters (four preferred). Sat, 07 Sep 2002 00:00:01 GM

But drupal is generating pubDate as
Sun, 2 Apr 2006 00:56:31 +0800 where as it should be
Sun, 02 Apr 2006 00:56:31 +0800