I am confused, the post you linked to shows someone having tons of problems with 1.2.1, can you point to someone who has NO problems running ML on 1.2.1?
FYI, ML does not run with firmware 1.2.1, it requires 1.1.3 and it uses a special variant of that firmware which has to be installed to enable the bootflag.
Please take the time to read all of the step by step instructions to install ML raw, and familiarize yourself with all of the pros and cons of doing so.
If you're not willing to read the many pages of documentation, or unable to search for the relevant information...you might want to re-think your desire to use ML.
P.S.
I think using a hack which is not even in Alpha stage on a paying job is...how can I put this nicely...unwise.