This might seem as an odd thing, but I have a need where I want to combine syslog as well as json in the same message. Syslog should be combined (without the message field) with the complete $raw_event as json. I've successfully converted the entire thing to json with 

$json_message = to_json();

However when I attempt the same thing with to_syslog_ietf(); an error is thrown. How would I achieve this behaviour with CE?

Couldn't parse Exec block at C:\Path\nxlog.conf:58; couldn't parse statement at line 72, character 42 in C:\Path\nxlog.conf; function 'to_syslog_ietf()' does not exist or take different arguments.