Obama's lawyers are, quite intelligently, refusing to play along with a man who is clearly a kook. They want to get his suit dismissed, rather than taking an action (delivering the birth certificate) which could be implied to mean that they take his case seriously. Obama's campaign position is that there is no doubt that he qualifies for the Presidency, therefore they are not going to deign to respond to Berg's actual allegations- they're just going to get his cased dismissed before it even gets to that point.
Obama Blade! Missing filing dates will not get the suit dismissed.