Windows 7 has a different hash-table. You can find by using IDA on the pidgenx.dll from Windows 7. I think that the function SetInfo is some what different for the old style keys, but I am not sure yet.
The pkeyconfig.xrm-ms file seems to contain the RefGroupID of Windows 8 products as just 206. How is it being mapped to the groupID being generated by the decoder i.e. 0x6fa, 0x6fb etc. ?
That is easy. The RefGroupID and groupID are the same. In the pkeyconfig.xrm-ms file you see the decimal value. If you convert these to hexadecimal you will have the value that KeyInfo needs. The value 0x6fa is in a hexadecimal notation.
So, with all this analysis and debugging, do you think something useful might be able to be accomplished, such as modifying the KMS server to activate ProWMC and Core installs using a KMS client key?