Syslog Output only transferring the "message" field

[Grimlock]

Nice, thats a good idea. I am using a ruby filter to create a new field named "combined_data" using code => ' event.set( "combined_data", event.to_json ) '

However, my syslog output still only transmits the content of the message field. My configuration looks like this:

output {
   syslog {
      host => ...
      port => ...
      message => "%{combined_data}"
}