Sounds interesting, but when I install the add-on, after restart it opens the Configuration Wizard, but the window is void, blank, and I can only click "Finish" (that leads to no actions) and "Cancel" that leads to unistall the product.
I must admit that in comparison to other similar addons (e.g. to more popular Google Docs Viewer addon; Docs Online Viewer addon; Open with Google Docs Viewer userscript) this addon seems to be the best one.
One only drawback is a first-run behavior -- when a user refuses to run the wizard (assuming to configure the prefs later) this ext uninstalls self. Of course it'll turns clear but only on the /last/ wizard page with a lic. acceptance checkmark. This UI algorithm looks a bit per... sorry, reversed.