Glad to hear it works for you. The strobe I have is the neonlite from bonica. I bought it 5 years ago or so. I have no sync cord, just the slaves on the strobe. I have tried turning the flash power up & down and it works with all the settings. My best guess is the same as SamT's, that it does not emit a pre-flash because you are inputting all that data your self in manual mode. Try contacting Bonica directly to find a strobe, I have found them very helpful in the past when I needed to look up parts in their warehouse. I will post my pics in the New Year.
Thanks, I just looked at your Boncia neonlite online and found that they have a newer model the XP, that can fire with or without a preflash. Made to work with all cameras with a preflash or without.
I typed in "Boncia" on B H Photo's website to find a pretty good deal on the strobe head, tray and arms included for $259.
Bonica | Neon-XP Underwater Strobe | NEONLIT-XP | B&H Photo Video
This is from their site-
The Bonica Neon-XP Strobe is a powerful underwater strobe light. Since the strobe will fire with 4 different pre-flash setting as well as no pre-flash it works with any underwater digital or film camera that has a built-in flash. It fits the Bonica Snapper-XP perfectly. It will enhance the picture quality in poor lighting conditions. It also reduces the backscatter problem that normally will occur when using a camera with built-in flash.
Along with manual control a microprocessor controlled exposure sensor automatically regulates the intensity of the flash to provide proper exposure at apertures from f/2.0 to f/4.0. Say farewell to trial-and-error lighting adjustment, it puts point-and-shoot simplicity back into the hands of digital photographers.
The Strobe also has a fully adjustable arm and flash head that swivels 360°. This will allow you to aim the flash in any direction. The Neon Strobe Light has dual sensors, this allows the strobe to fire simultaneously when the camera flashes without the need of a sync cord.
Double silicone seal rings give better protection from water leakage. A second Strobe Light can be attached on the support tray if additional lighting is needed.
Key Features
• Slave will fire with 4 different pre-flash settings as well as no pre-flash
• Microprocessor controlled exposure sensor automatically regulates the intensity of the flash
• 60° angle of coverage
• Recycle time of 0.3 to 5 seconds
• Up to 120 flashes with full power batteries
• 5700° kelvin color temperature