no idea, how to get load/save states on mupen64 working?

i tried also changing this lines in /retropie/opt/retropie/configs/n64/mupen64plus.cfg (will not be overwritten by autoconf):

# Joystick event string for saving the emulator state
Joy Mapping Save State = “J0B8/B7”
# Joystick event string for loading the emulator state
Joy Mapping Load State = “J0B8/B6”
# Joystick event string for advancing the save state slot
Joy Mapping Increment Slot = “J0B8/B5”

take the button numbers from /retropie/opt/retropie/configs/all/retroarch-joypads/LogitechLogitechRumblePad2USB.cfg
input_select_btn = “8”
input_l_btn = “6”
input_l2_btn = “4”
input_l3_btn = “10”
input_r_btn = “7”
input_r2_btn = “5”
input_r3_btn = “11”

input_enable_hotkey_btn = “8”
input_load_state_btn = “6”
input_save_state_btn = “7”

load/save works in snes-emulator with the retroarch-config and the config in snes/retroarch.cfg (same buttons, but config-keynames differ):
input_player1_select_btn = “8”
input_player1_start_btn = “9”
input_player1_l_btn = “4”
input_player1_r_btn = “5”
input_player1_l2_btn = “6”
input_player1_r2_btn = “7”
input_player1_l3_btn = “10”
input_player1_r3_btn = “11”
input_enable_hotkey_btn = “8”
input_exit_emulator_btn = “9”

is that right? i did not found any explanation of the button-numbers.

regards Frank