Originally Posted by srclark 
The AF540 has a sync port, but it's the pentax f5p connector, it's not a generic pc port.
So the question is I guess, is there an adapter to go from the pentax specific port to a generic PC port. I haven't been able to find one.
I realize the p-ttl will not account for the light from the manual flash. That's actually an integral part of the lighting setup I have in mind.
A 5p cord and a Off-Camera Adapter F should be all that is needed. Place the Cybersync in the Off-Camera Adapter F, run the 5p cord from the adapter to the AF540 mounted on the camera and I think you're done.
Pentax Flashes and Flash Accessories 
If that doesn't work, then you'll need to add a Hot Shoe Adapter F
The setup would be Hot Shoe Adapter F on camera, AF540 mounted to it, 5P cord attaching the Off-Camera Adapter F to the Hot Shoe Adapter F, and the Cybersync mounted on the Off-Camera Adapter F.