rjsimp:
...When I looked through the manual, if I have it set to external only, I can't see anything that say's it would fire the internal as a fill flash. The only thing I see is it will fire the internal if the external is not connected.
You know, I thought I read it carefully but you are correct. It looks like I was looking for a description of what I was experiencing and reading into it more than was there. I read this as meaning the internal flash would fill unless turned off:
In S mode and M mode, the flash mode changes in the following order:
fill-flash | red-eye fill-flash | flash off.
And then when I saw this I read it as meaning I should turn off the flash since the external one would not be affected:
The camera’s flash mode will have no effect on the external flash. The external flash will fire even when the camera’s flash mode is set to off.
And finally, I neglected to discern that
together here means when both are selected in the menu:
When the built-in flash and the external flash are used together, the built-in flash is used as the compensating light source.
In any case, with the Ikelite interface, it does indeed actually work correctly when I chose external only and then turn off the flash. So, I either have a defective one or it is just a fluke in the Ikelite design. As long as it works I am happy.