After some months I actually found out by coincidence that I just have to go to the Key settings in FH2 and delete the Joystick configurations from the "tank"-menu (which got there be themself? They are copied from sth. I guess!). So, I think now, what a pitty I always wanted to drive tanks since 2.4 but had this strange problem my tank was always driving forward without pressing any button!!! So aiming got VEEEERY hard, releasing, tapping, releasing, ... the key "S" (backwards)... So guys, could you inform new FH 2.4 players about this issue somehow ingame (in the settings menu under "tank"-key settings???)?
Would be VEEERY helpful since I won't be the onlyone having experienced and wondered about this problem until finding out by coincidence that it's the Joysticks responsibility... -.-