TFC water works now with the Archimedes screw not for the manual addition of water to the Boiler. Right clicking with a Redsteel Bucket still brings up the GUI instead of adding water. When i first tried it a couple versions back only Vanilla Water worked with the screw now it dose not. I have not tried adding the initial water with a wood bucket. I will check that when i get home.
Bonus: Did you know you can move TCF Water source blocks down hill with Sluice boxes before you have Redsteel? They create another source block below the Sluice Box when properly placed. If you have water up above were you want your farm you can make a channel down to place the water in the middle of your 9x9 field.
It sounds like the TFC Water Compatibility mod is only partially working with Flaxbeards right now. Feel free to disable it and try using the vanilla water as long as your using Flaxbeards, Railcraft and the others should work fine with TFC water. I will continue to try contacting the dev for it, but he seems to be out of touch at the moment