Hi the file in

/System/Library/PrivateFrameworks/Install.framework/Frameworks/OSInstall.framework/Versions/A/

is named Install, not OSInstall anymore. I'm not able to install to MBR. A patch would be fantastic.

But for the moment I'll do a neat trick: format a fast USB drive as GPT and install the Lion ; ). I'll try it and tell you if it worked.

UPDATE: worked but took a while.