I figured out how to make the books work in the Touchpad Kindle app! Note that this will only get the books into the Kindle app and make the readable (and the links to sections of course work), it's not going to include an automatic action chart or inventory catalog, like the program that can be downloaded from the website.
First, install Preware to the Touchpad, following
this guide. That done, open Preware and search for "kindle". This brings up
Kindle Import, that you need to install to be able to side-load to the Kindle app.
Unfortunately, Kindle Import requires that files have names of a very specific format. I've copy-pasted the way I named the first 20 Lone Wolf books in under the spoiler below, to make it easy for you.
Once you've renamed all your downloaded Lone Wolf books, you need to manually move all of them to the the .palmkindle folder on the Touchpad. You may need to tell your Windows to show you hidden folders, try that if you can't find the folder on your first try.
Once all the renamed books are in the folder, open Kindle Import on the Touchpad and press Load New Books. Verify that the app has found all your Lone Wolf books (I skipped a space in one book name and had to redo that one), then press Import Books, and watch the magic happen.
All the Lone Wolf books should now be in your Kindle library. Note that you don't get the covers with this method, but since I use list view I don't care about those.