hey gruss its good that you are testing and good that some members are giving you some decent sujestions and help.
did you keep the old sensor?
whats the ohms/resistance reading compared to the new one? i know you want to use the scope but at least you can prove it to any doubting party's. it will be a dif reading but may prove your point

you can bench test it off the car with muilti meter and propane torch using a muilti meter or scope maybe? its old school but so is your sensor
connect vice grips to the sensor body threads sit on bench connect the ground lead from meter on grips and conect the signal wire to positive , set on 2 volt scale not auto or connect the scope for timing which could be interesting. get propane torch (b&q 8 quid) light it up and heat the sensor tip moving flame constantly it should reach .9v or 900mv within 60 seconds, then pull away it should go back to near zero or origional voltage within 3 seconds , if neither of these are met then its fcuk'd or if its reading a high voltage before heating

someone may shoot me down

and i know you wana use the scope to test but at least you can bench test prefrebly with scope as you will be able to see the exact times. and post the proof

the propane can be used to feed into the engine also to do the same test on the car to drive it to 900mv rich then pull an air pipe for the lean test whist car running which i think someone commented on but never actually told you how