I made it working by putting the second dll in a folder that's part of windows system path. Also, after exporting release build and installing it, application didn't work until manually copying the dll into same folder as exe file. The fact that it already exists in "\META-INF\AIR\extensions\..." subtree didn't help much.
It's far from perfect, but at least it works for development. Hope this info can help someone. Cheers, Tomislav
