OK, I think I understand it now. Android automatically re-routes audio streams (input and output) if USB audio devices are connected. However, applications can insist on using the system inputs/outputs instead of the recommended ones. It looks like Skype behaves like this. Regardless of the configuration it tries to open AUDIO_DEVICE_IN_BUILTIN_MIC, even if it doesn't exist, but USB input devices are available.
So there are two options:
1) Ignore it, since it is the standard Android behavior and complain to Skype developers.
2) Re-route the input stream from the system to the USB device (if available).
I'll wait until you guys have tested WhatsApp and Viber. If they are implemented to use the recommended input device (which seems to work now), we will probably stay with option (1). Otherwise we will look into (2), but it is quite an overhead. The new version will be released Tuesday or Wednesday.
