There has to be an earlier birth certificate — his Mother only met Soetoro years AFTER Barack was born. He may have been adopted by his new step-Father, and may have gone under the name of Barry Soetoro, and that may well be his legal name, but what we want is his ORIGINAL birth certificate.
At this point, even if he proves that everything’s above-board with his original birth certificate, there’s still the matter of the fake one. A senator forging his identification is not going to endear a man named Barack Hussein Obama to the American voter.