This really isn’t supported. You might be able to roll something yourself via FX Factory and the Syphon QC plugin, but its not going to work as well as something authored to be persistent as a Syphon output.
It is, frankly, not on our radar at all right now. You could request some development from a 3rd party, or attempt to write something yourself.
But, to be short, we don’t plan on supporting this or even attempting to test it. The current FCP plugin design is a jury-rigged – should not work as well as it should – and thus to be avoided – as documented – plugin. Avoid unless you want to pull your hair out.
Sorry about that.