Webplayer - How to preserve aspect ratio in full screen?

Hi,
I’m trying to set my webplayer game to full screen but I can’t preserve the aspect ratio.
I tried using Screen.SetResolution and changing the default resolution in Standalone Player Settings.
What else can I do?

Edit: My game works at 3:2 aspect-ratio. Native resolution: 1080x720

Use Direct3D 9 instead of 11 => boom, it works! (at least for me)
And I have no glitches with D3D9, whereas with D3D11 my windows are a bit messed up once I leave fullscreen mode in my web player game.

It’s true though that the desktop resolution settings corresponds (roughly) to the web player fullscreen resolution setting, but only with D3D9.