openHAB 3.3.0-SNAPSHOT Z-Wave Binding and link to GPIO Input

Hello all.
I am using a Raspberry Pi Model 3 2015 with installed openHABian 3.3.0-SNAPSHOT version. On the Raspberry is connected the RaZberry Z-Wave tranceiver. Now I am trying to trigger an input from GPIO interface to control an enrolled Z-Wave device (via Z-Wave Binding). Via the “Rules” configuration on openHAB I had no chance to send an ON command to the Z-Wave device. I am using GPIO 21 as pulldown input and a Z-Wave Power Switch device for activation. Any idea in this case?
Thanks a lot,
Luciano