To be honest the keys and subkeys you've mentioned were the first ones I tried too
(I also thought that they might be the logical choice for a program checking the OS type) but that didn't seem to have any impact on the Antivir installer while the "ProductOption" keys worked.
But maybe, there might also be programs, on which changing the "CurrentVersion" keys and subkeys is the important step to install them.
Up until now, I didn't notice much programs that denied the installation after tweaking the .msi anyway
So my experience just relies on Antivir PE and Sunbelt Kerio PE (which won't work under Vista anyway ^^).