How would I attach a Sonos Beam underneath an HDTV mounted to a Murphy bed?

We are installing a Murphy bed in our house. Because of the lack of wall space I want to attach the HDTV to the Murphy bed and ideally I would like to have the Sonos Beam attached to the HDTV mount so that it is below the HDTV and would be secure when the Murphy bed is in use. In other words the bracket would be have to be able to hold the Sonos beam even when the bed is open. Any ideas? I also need some suggestions for an appropriate HDTV mount for the Murphy Bed.