Help with a mapping modification

First of all excuse my english and i hope you will understand what i mean. I want to make a loop and change his length in flux mode. But i don't want to do it with the rotary encoder from the loop section. I want to make it with the buttons from the grid .Since i don't use tempo bend, tempo adjust, master set and bpm x2 and /2, i deleted them and left only the command for flux mode. I don't know much about mapping so i did the following thing. Add in "loop size select + set", learn the button i want, set it "type of controller" to "button", "interaction mode" "direct", set value ... to a value. But now the following thing is happening. The flux mode do not activate anymore (even if the button is blinking), and when i press the button that i mapped with a value, the respective loop stays on and i have to deactivate from the loop section.
I specify one other thing . If i do it with the rotary encoder from the loop section , everything work flawless.
Hope you could help me and thanks in advance.