Why would you want to connect an Oxygen sensor to a L6 ecu?
The L6 does not have an input for an Oxygen sensor and I doubt the hardware for it is present if you assume it's the same pin as in the L8..
Also the software that is used will not do anything with a signal from the Oxygen sensor.
Furthermore the standard Eprom is completely full with the standard program and there's no room for a Lambda control strategy.