Hi,
My first thought on this is that you mentioned only a few drops of Diet Coke got between the contacts and the port. The first advantage of this is that it's DIET coke right? That illiminates sugar from the equation.
The second advantage is that gravity probably is working to your advantage. i.e. it is better to have the cradle die than the PPC. Finally, the thought that your e800 was ruined by a few drops of diet coke seems impossible. The device itself was made to resist things like dampness, small stints in the rain, etc.
With that said, I have a theory and an idea on how you can fix it. I can't be held responsible for any damage that occurs, but if you want to try.. My theory is that you had more than a few drops seep into the
cradle and it's shorted the circuitboard in the cradle. Not having a Tosh cradle in front of me you are going to have to eyeball the situation yourself. But basically, a torx-6 screwdriver is almost standard for working on PPC stuff so if you could find one of those to take the base apart. If not, sometimes a flathead jewler screwdriver will work.
This isn't too much brain surgery, so don't worry too much. The cradle itself looks ominous from the outside, but it amounts to a small circuitboard (estimated 2 inch by 3 inch) with the USB cable attached to it via it's internal wires (red, green, black, etc.) and a power plug. Anyway, you really don't need to worry about what wire goes where, because you aren't disconnecting anything. However, be gentle and remember how the cable is looped through the plastic (take a picture with a digital camera if you have one). Once you have everything apart, I am going to assume you have a damp or perhaps "gooey" circuitboard that needs to be cleaned. I'd use circuitboard cleaner from Radio Shack --- but since you are in Japan, it's hard to say what I'd use (at least in a public forum) but I would find something - windex, rubbing alcohol, something...
Clean the board paying close attention to the DC power jack and the area surrounding it.
While the circuitboard is drying, clean the inside of the cradle really well.
Once absolutely dry, here's the fun part if there is a fun part. Once the internals are DRY (did I say dry? because if not, make sure it's dry), gently plug the circuitboard into your PPC and then gently take the cable and plug it into your USB port ONLY (DO NOT PLUG THE POWER IN). Make sure you aren't touching the circuitboard with your fingers or letting it touch metal. It should suspend rather well from your PPC itself.
If everything is cool, then you should get a connection. If so, immediately disconnect the cable from the computer FIRST and then disconnect the circuitboard from your PPC SECOND. Reassemble and you should be happy.
I have to run to a meeting right now, but this should get you started.
Brad