Converting An Enterprise Edition Database To Standard Edition

Recently I could not answer one question. Since Oracle Download page gives one setup file for Standard Edition One 11g, Standard Edition 11g, Enterprise Edition 11g, how can I install Standard Edition One 11g only?

During setup I will not choose any options, is this enough? I don’t think so. In Oracle My Support I found some clues for version 9 [ID 139642.1]. But it says just to drop some system users like MDSYS.

So the question still open.