The Sony P1 (rather than the T1) is what I presume you're diving with, given the Marine Pak housing. I think it first came out in 2000 or so, and for a while this was just about the best 3.3 MP compact camera around. I still have one, with a Marine Pak to boot, though I dive with a Canon S70 now. I don't think they're that common, as it was one of the earliest digital camera housings. Where'd you get yours?
You will need to use a fiberoptic cable link, or something like the Ikelite DS series with a sensor that detects the camera's flash and triggers the strobe. Inon doesn't make an adaptor for the MPK, or I'd recommend the D2000. Check out the Ikelite DS-50 with wireless strobe sensor, or even the manual controller. You may have luck with the SeaLife digital strobe and tray, which uses a fiberoptic link to trigger the strobe, and doesn't require the base plate and lens adaptor that the Inon uses. I only have personal experience with the D2000.
I've been very happy with my P1. The Marine pak was solid, and has never given me problems (I still use it for watersports, mainly kayaking). Good luck.