Really annoying problem that i cannot work out... please help

i'll start at the beginning...

Shot a 1080i project on sony FX1000

captured in HD in final cut, completed project, exported using compressor "DVD best quality 90 min" setting

import into dvd studio...

project resolution is 720 x 576i
display mode 16:9 letterbox

i burn the project, now....

when i play the dvd on my 16:9 television, it does not fill the whole screen. It squeezes the picture horizontally and gives me black bars top and bottom. Why is that, if i shot it in 16:9, burnt it in 16:9, and my tv display is 16:9, why am i getting a stretched out dvd picture with the black bars. I want it to fill the whole screen (no black bars) without warping/stretching/squeezing the picture.

Please help....

Bobby