I am using Subal's old tubular black plastic flash housing, which was originally developed for the SB24 and SB26 but also fits the SB28 and SB80DX! There are quite a few available on the second hand market (in the UK, at least).
I guess, Don, that you are referring to the new SN80 housing? I haven't seen it yet. But have heard it offers full control over the flash.
My housing offers no control over the flash and you have to remember to switch it on before the dive.
I have found that DTTL works really well. Used it to shoot 70 keeper shots of fish on this afternoon's dive with Sigma 28-70mm.
So in short the kit works. But TTL is not essential (as we all know) for digital. But I have to say that given the option, I much prefer it.
You can judge the results from today at
http://homepage.mac.com/mustardoni/
Alex
Be aware that once you wire a D100 or D1 housing for DTTL it will not let you fire Nikonos guns (even in manual)!