Exporting HD in Premier Pro

[videopetur]

Thers something that confuces me.

I shoot everything in HD, so when I import my clips from the camera (JVC GY HD100) to Premier Pro I make a HD project, 720p, and I expect it to be 1280x720, and it seems to be.
But, when I have edit and I export the product uncompressed (export movie .. .avi) and mark the file just in the windows file-mannager, the filemannager says its a 576 pixels high file, why?

But, even it is a 576 file Vimeo tells me its a HD file.

[videopetur]

Exporting in Premiere Pro CS4.
In CS3 there was a export movie, and I got a .avi file of same quality as the file I was working on.
It was fast, it took no time to export the file, becaus there was no encoding going on. The format was automatic, I didnt have to wory about framerate's and what not.
It says in the manual that exporting uncompressed quality in CS4 is: pics uncompressed Microsoft video, and there you go, but:
1 it takes ages
2 it encodes the video
3 the mediaplayer strugels when playing it back.