In the bucket, have two holes with rubber grommits. One for the racking cane, the other for a piece of copper or ss tube clamped to your hose from the CO2. (I found the hoses too hard to get a good seal and still get through the grommit)
Turn the CO2 all the way off, regulator to absolute zero.
Take your racking cane and connect it to your liquid out side of the keg, Open the keg to atmosphere (purge with CO2 if you like, but you need to let the pressure bleed out)
Place the keg below the fermenting bucket.
Then slowly open the regulator until you hear gas flowing or beer fowing, then stop opening the regulator, and maybe back it off a half turn..
Essentially, you are still siphoning, and just using the CO2 to start the beer moving and then filling in the head space. The pressure needed to keep the beer moving often causes the lids to pop over time, so keeping the pressure low is the key.
Good luck (FYI, if you need to make a second grommit hole, you can pick up the grommits at some of the popular mail order homebrew shops.. I am lucky that my local one has a stock)