I agree with those who state that using an optical sych cord works with the S2000. I have the TG-6 & Oly housing and bought an Inon S2000 specially for this rig due to it's size. I have found it works perfectly for me in macro and longer-range shots (when vis here allows). I do use a sync cord.
I also find some kind of focus light is nice. I have a Big Blue spot/video light that I like; I usually keep it on the lowest wide-angle setting (not spot) and it works well for video and focus.
What cable did you use? There are a ton of options on divervision.