I use the flash to trigger some studio flashes. This effectively gives me rear curtain sync
with the studio flashes, allowing me much control. The pre flash, of course, fires the
studio flashes. I need to stop this behaviour.

Kind regards
Kevin

That would make sense, but how can I change out of P-TTL mode into a mode where
it does not fire a pre-flash. All I can make it do is switch between P-TTL and SB

Kind regards
Kevin

When I set my AF-360 to rear curtain sync, if fires a flash as
the curtain opens also, how can I stop this and why does it
do this?