Bluetooth v2.0 USB stick+A2DP-enabled headphones. How do I make sure A2DP is used?

[Sash[DSL]]

Headphones: Sony DR-BT10CX Stereo Bluetooth Headset
USB stick: D-link DBT-122
Windows XP professional

Installed the drivers, everything seems to work fine. However, I have never used BT headphones before and got nothing to compare the sound quality to. To pair the headphones with PC, I go to My Bluetooth places, select Sony DR-BT10CX Stereo Bluetooth Headset, choose enable. However it does not tell me whether the HSP profile is used or the A2DP. Any way to check?

[Impossibles]

I'm pretty sure it just automatically uses the correct format, kind of like USB 1.1 vs 2.0, you don't need to toggle anything.

[Bskll]

the sound quality will be very noticeable even if you don't have non-a2dp headset to compare against. just plug in a regular headphone into computer and play music, then play it on headset, if it sounds significantly crappier, then you're not using a2dp.

[Sash[DSL]]

Thank you very much Bskll & Impossibles! You are absolutely right, I tried the same headset using the Hands Free Profile(HSP) and sound is dramatically worse. Therefore, Stereo Audio must be the A2DP.