Just a quick update: I updated my Nokia Qt SDK with the latest and the on-device debugging seems to work now, although it's a little bit slow (at least over wlan, haven't tried with USB yet). I was able to debug the parts that were causing me headache the most.

Now I pretty much need to package the thing correctly and submit it again. Anyone that knows how to do that with Qt SDK on windows? I would need to add a config file to the deb package as well.