There are many ways to get somewhere, but here's a general list of things you have to do:

1) Think for a little bit about what you have got and what you want to do

2) Do research. Has this been done before? Have similar things been done before? (Usually the answer is yes to either question)

2) Think whether it's theoretically possible to do what you want to do with the information and parts you have (in this case: there is a working driver for Linux and Windows, but they're closed-source)

3) Fixing computer things usually involves a lot of debugging (tracing). Will tracing help us out here? What tracing tools/skills do you have, what tracing tools/skills would you like to have? Often you'll need to extend the tracing skills/tools you already have, but normally you don't want to spend too much time on this. (In this case, we can trace without any specialized equipment -- we just need a virtual machine.)

4) Once you have the appropriate traces, take a good look at them (you'll probably want some scripting abilities here) and see if you notice any patterns (e.g. "lots of data after this", "just a little data after this", "this bit of data is always the same", etc.)

5) If you don't know what to do at this point, maybe go back to the tracing step