Thank you, @gazdav787 , you've given me the clue I needed! Besides those variables, I've identified these ones:
The buttons can be toggled using R_TRP_Climb, R_TRP_MCT, R_TRP_TOGA and R_Mstr_Climb. Send a 1 to those values and button will change state if it's possible.
State of the buttons can be read using R_TRP_TOGA_redu_il1, R_TRP_TOGA_redu_il2, R_TRP_TOGA_redu_il1, R_TRP_Mstr_eng1_il1, R_TRP_Mstr_eng2_il1, R_TRP_MCT_il1, R_TRP_Climb_norm_il1 and R_TRP_Climb_max_il1. Each variable maps to a different state.
Value of the display can be read using JF_RJ_TRP_Display_Value.
Thanks!