Hi Sven,
i didn´t find a solution which is integrated in the binding
I´m using a workaround discribed by underpop in this thread:
https://community.openhab.org/t/solved-rfxcom-binding-with-rfy-protocol-and-asa-subprotocol/11495/10
This works, althought I sometimes have problems, of which I believe that they are due to the fact that it takes longer to start the external program for the command and/or the acces to the interface over two ways.
You have to test this.
Good luck
Hans