Originally posted by Just1MoreDave Set up flash for rear curtain sync. Put camera in M mode. Set shutter speed to 1 second or longer. Shoot. You might see a P-TTL preflash when you hit the shutter. If rear curtain sync is working, you should see the real flash just before the shutter closes.
To elaborate a bit (because I was in the same situation with my K200D, and it took a while for me to understand the directions of the K200D manual):
You will need a flash that supports the Pentax way of doing trailing curtain sync! The camera body will need that information from the flash and not vice versa.
Example: I have a Metz 44 AF-1 that would be happy to operate in trailing curtain mode, provided that the camera body tells it to do so --- and that's exactly what my K200D won't do. If on the other hand I had had a genuine Pentax external flash, I could just set that flash up to this sync mode and the body would respond accordingly.