Problems with LED trigger "rssi" / rssileds

Hello!

I'm using OpenWRT as a simple repeater / router, which works fine. wlan0-1 (192.168.100.0/24) is routed to wlan0 (192.168.1.X).

Now, I want to add some "signal meter" for indicating the signal strength the repeater is receiving. I want to use rssileds and am using this HowTo: https://openwrt.org/docs/guide-user/hardware/led/generic.rssileds#led_definitions

Saldy, it doesn't work. I have edited the /etc/config/system using "joe" to

config system
        option hostname 'OpenWrt'
        option timezone 'UTC'
        option ttylogin '0'
        option log_size '64'
        option urandom_seed '0'

config timeserver 'ntp'
        option enabled '1'
        option enable_server '0'
        list server '0.openwrt.pool.ntp.org'
        list server '1.openwrt.pool.ntp.org'
        list server '2.openwrt.pool.ntp.org'
        list server '3.openwrt.pool.ntp.org'

config rssid 'wlan0'
        option refresh '40000'
        option threshold '1'
        option dev 'wlan0'

config led 'led_usb'
        option name 'USB'
        option sysfs 'tp-link:green:usb'
        option interval '50'
        option default '0'
        option trigger 'none'

config led 'led_wlan'
        option name 'WLAN'
        option sysfs 'tp-link:green:wlan'
        option trigger 'phy0tpt'
        option default '0'

config led 'rssilow'
        option name 'RSSILOW'
        option iface 'wlan0'
        option sysfs 'tp-link:green:lan1'
        option minq '1'
        option maxq '100'
        option offset '0'
        option factor '6'
        option default '0'
        option trigger 'rssi'

config led 'rssimedium'
        option name 'RSSIMEDIUM'
        option iface 'wlan0'
        option sysfs 'tp-link:green:lan2'
        option minq '30'
        option maxq '100'
        option offset '-29'
        option factor '5'
        option default '0'
        option trigger 'rssi'

config led 'rssihigh'
        option name 'RSSIHIGH'
        option iface 'wlan0'
        option sysfs 'tp-link:green:lan3'
        option minq '70'
        option maxq '100'
        option offset '-69'
        option factor '8'
        option default '0'
        option trigger 'rssi'

After saving with joe I use uci commit

But the LEDs stay dark. Even after reboot. Also in LUCI, the triggers for the lanX-LEDs show "none".

What am I missing?

Greetings and thanks from Germany

René