Aspect ratios

Hi all,

I've an issue that's melting my brain and could do with some advice.

I took some footage on a panasonic dv cam in widescreen aspect ratio.
I dump it onto the pc and if i look at the properties it says that the aspect ratio is 720x576. Yet to view it, the footage is clearly in widescreen ie 1024x576. I put it into PPro and again it 'looks' like perfectly normal widscreen when on the timeline but the clip properties says 720x576.

I edit and export the footage using 'match sequence settings' which exports it again to what appears visually as widescreen(but still the file properties still say 720x576). However, when I upload it to vimeo/youtube it will be squashed along the x-axis. What is going on? And is there a way to change the export 'aspect ratio' in PPro to 1024x576 so that it definitely, positively is widescreen?

thanks

J