The D2000 offers a bunch of modes providing automatic control as far as possible depending on the camera used:
1. S-TTL based on the camera TTL metering (preflash TTL cameras)
2. external auto strobe with aperture preselection based on the strobe's own metering / external sensor (no preflash required)
3. manual power settings
This helps if you want to reach for every auto control you can get.
But external auto strobes have drawbacks: external sensor has always a different field of view and point of view compared to what the camera sees and records. Especially macro can be a pain (in the past external sensors often had a measuring angle of ~ 40°, independently from the lens FOV).
As TTL is not possible I wouldn't struggle around with the auto mode but switch straight away to manual. I even would recommend using manual power settings if TTL was available. With a DSLR manual control is easy as you have a wide range of apertures to control the strobe lightning (depending on camera/lens even down to f45 with macro).
BUT your Z220 features so much manual settings down to -5 which equals 1/32. So even if your camera provides f8 as the smallest aperture I guess you will be able to obtain proper control even for critical macro work.
I strongly recommend keeping your dual Z220 (have them as well) and just trigger them with optical cables in manual mode.
Having that said I haven't used a Fuji 810. So you should confirm that this camera doesn't emit a preflash in order to work properly with the Z220's manual power settings.
I've commented this in a recent thread concerning Fuji 810 and Inon D2000 strobe:
http://www.wetpixel.com/PNphpBB2-viewtopic...ic-t-7454.phtml
regards,
Julian