The pilot was landing at a remote, off airport site in an experimental homebuilt, tailwheel-equipped airplane. He stated that he made two passes over the short strip, and while setting up to land on the third pass, he lost sight of his intended touch down spot and landed longer than he had anticipated. After landing he applied the brakes heavily and the airplane nosed over, coming to rest inverted. The wing struts were substantially damaged. The pilot stated that there were no preaccident mechanical anomalies with the airplane that would have precluded normal operation.