In Euro Truck Simulator 2, you can stream live radio streams within the game.

All my currently bookmarked radio stations in the game stream perfectly when Teamspeak is not on.
However, when Teamspeak is on - the game acts like it's playing the radio stream - but no radio comes through the speakers at all.

If I turn Teamspeak off, the radio comes back.

Before posting here, I looked around on the Game's forums etc (SCS), the only thing I found out was that ETS2 outputs radio streams using Direct Sound. Therefore I dutifully changed the options in Teamspeak to use Windows Audio Session instead for input/output device, but no dice - Problem persists.

No other sound from the game is affected, just the radio stream.
The streams work just fine with TS on if I'm using vlc/wmp. But that's not as convenient as the in-game radio player.

So the question is, does this seemingly game-specific issue happen for anyone else and, Why is it happening?

Because I have messed with all the audio related settings in the game, windows and teamspeak itself and, I am no closer to solving this - in fact it has me perplexed.

I have one mic, and one output device (Microphone/Speakers - VIA High Definition Audio).
OS is Windows 7 (x64) Ultimate.