PS4 DS mapping Triggers ( L2 / R2 )

Hello, I've been trying to map the L2 / R2 button to the game i'm making without success. According to various post i read like this, thoses corresponds to joystick button 7 and joystick button 6. Also according to this image, those work on the 4th and 5th axis ( most lkely to evaluate the pression operated on the triggers ). Therefore, no matte what i do i dont seem to be able to get reaction from my game when i bind something to those joystick buttons ( it works totally okay with square circle traingle and X ).

So how does the mappings with the triggers works ? Do i have to insert values in Negative/Positive button ( on unity input mappings editor ) ? i set them to joystick button 7 ( R2 ), the type would be Joystick Axis, is also set Axis to X ( tried to 5th axis ).