I found a workaround for Zend Date's DST Bug, but the workaround introduces another bug. The workaround simply sets the time twice. This introduces another bug, if the resulting date crosses the date boundary, the the day get incremented or decremented.
I am wondering if there's a way to determine that the date at hand is a "time change" date, so that I can come up with a solid workaround to the Zend Date DST bug.