Changing Video Resolution Bttv Driver

HI,

I am trying to get the video resolution of 720x576 from IDS Eagle video capture card which uses uses Bttv878 chipset.
The capture card supports video resolution of 720x576.
The problem is i am always getting the interlaced video with resolution 320x240.

Can someone help in understanding how to configure Bttv Driver to get video resolution of 720x576.

OS: Ubuntu 11.04
Capture Software: c++ application that uses video4linux


Thank you,
Venki