Of course the birthers have been asking for evidence. What I said was that they'll reject any evidence they're given if it doesn't support the conspiracy theory.
What is your explanation of the fact that Obama's birth certificate (pdf file) is a forgery? So far no Obot could provide instructions on how to scan a document and end up with a file that has a layer that contains only a date and another layer that contains only a signature. Please give it a try.