Originally posted by Bulldogface I guess you are right. Or as Pentax says, it was meant to fire in P-TTL in multiple-flash mode
I think that's the key... Pentax really wants you to use P-TTL. Thinking back, that is probably why I ended up with a Metz flash when I had narrowed my choices down to the two flashes you have. I got really used to manual flash use with the AT-280 flash I had before, and the K10d I had at the time was notoriously bad with P-TTL.
I'd guess that if you had two Metz flashes, you'd have the results you want. The funny thing is it is incomprehensible that something with regard to having two flashes listening to a signal makes the Pentax flash jump the gun. It sounds like that as soon as you turn the Metz on it knows. Yet, it works fine if the Pentax is in PTTL mode. It almost sounds like there is some type of lens ego thing going on there.