I think Andreas is misunderstanding the Mac file type and creator codes. These are related to the Mac file system, and are not part of the OTF font file as created by the FDK.
Adobe has a little utility like the one described, but we didn't think to put it in the FDK. (Antoine, could you add this to the next release?)
If you're a beta tester for Adobe OpenType fonts, you can download the utility (OTF FileTyper) from the OpenType beta site.
We do have this file posted elsewhere on the Adobe web site, but the link is broken at the moment. Unfortunately, Adobe is closed next week, so there will be a slight delay before this is fixed.
T