i'm sorry but i will not extract the changes to a seperate project since its not my datatype and i didn't really make BIG changes on it. i only made it valid for php5 if i remember right.
but if you want you can of course feel free and take the datatype from my svn tree and replace it with the one from the original birthday extension. maybe that helps you.
also i will let georg know that you are interested in a update of his extension, he might will come back to you then.