If you have a saved configuration from the 6012 it should be uploadable to the 8811 without needing any modification since the two remotes are identical internally (unless you have an EEPROM larger the 2k in the 6012).
I just realized I misunderstood your question. I thought you were trying to upgrade an 8811 from a 6012. I think you're trying to install the extender on the 8811, correct?