"Use GPU acceleration" checkbox disabled

[peepay]

I did a clean install of Windows XP on my new PC yesterday, installed VLC and wanted to enjoy Full-HD capability of the graphics processor, which it claims to support, by watching a 1080p video. However, in VLC, when I go to Tools > Preferences > Input & codecs, the "Use GPU acceleration" option is disabled, gray, I can't check the box - and without this, the 1080p video playback is unwatchable. Any ideas why it's like that and how can I enable it?
VLC version is 1.1.5 and the graphics processor is Nvidia ION integrated on ASUS AT3IONT-I motherboard.

[VLC_help]

VLC doesn't support GPU acceleration on Windows XP. Only in Vista and 7.

[peepay]

Please say it's not true or that it is gonna be updated soon...
I invested in buying Full-HD capable motherboard just to find out that my favourite player doesn't support it on XP?
Now the only option left is to use Media Player Classic, which I didn't want to...
Whoaa - wait! I would have almost forgotten. I checked it today at work, I have Windows XP there as well and the option was active, I could check it. (However, I didn't have any 1080p video there to see if it actualy really works.) Now where's the truth?

[Lotesdelere]

VLC is using DXVA2 which is available on Vista and Seven only while XP is using DXVA1.
So there is no way that VLC can use GPU acceleration on XP even though the check box might be available.

[Jean-Baptiste Kempf]

The option box was available before on XP, but the code wasn't there.
So, in lastest version, the box is deactivated.

Sorry, mate!

[peepay]

And are there any plans on adding DXVA1 support in the future?

[VLC_help]

No.