with the workaround it works now.
//Schlafzimmer
Rollershutter Schlafzimmer_Rollo_1_Proxy "Fenster (Klein) [%d %%]" ["Rollershutter"]
Rollershutter Schlafzimmer_Rollo_1_Set {channel="homematic:HmIP-BROLL:OEQ0323223:00111A498E47B9:4#LEVEL"}
Switch Schlafzimmer_Rollo_1_Stop {channel="homematic:HmIP-BROLL:OEQ0323223:00111A498E47B9:4#STOP"}
Rollershutter Schlafzimmer_Rollo_1_Level {channel="homematic:HmIP-BROLL:OEQ0323223:00111A498E47B9:3#LEVEL"}
// Schlafzimmer Fenster 1 (Klein)
rule "Schlafzimmer Rollladen Control"
when Item Schlafzimmer_Rollo_1_Proxy received command
then if (receivedCommand == UP) {
Schlafzimmer_Rollo_1_Set.sendCommand(1)
}
if (receivedCommand == STOP) {
Schlafzimmer_Rollo_1_Stop.sendCommand(ON)
}
if (receivedCommand == DOWN) {
Schlafzimmer_Rollo_1_Set.sendCommand(100)
}
end
rule "Schlafzimmer Rollladen Level"
when Item Schlafzimmer_Rollo_1_Level changed
then Schlafzimmer_Rollo_1_Proxy.postUpdate(Schlafzimmer_Rollo_1_Level.state)
end