how to export h.264 interlaced video??

hi, my situation is the following: i have a full hd (1920x1080i50) camcorder which gives me just interlaced video clips with 50 half frames per second in AVCHD. i dont want to deinterlace the material, cause it taks too much time, the quality looses and the filesize is doubled (if i want to keep every frame).

i want to cut it with imovie 08 and then export it back into h.264 in interlaced format. (because i want to burn it to a data-dvd and play it in a playstation3. and h.264 is the only full hd format, which the ps3 is able to play, i think).

but in the export preferences i cannot choose between the options "interlaced" or "progressive". and the export with quicktime as h.264 or mpeg-4 is always in progressive mode, ignoring the interlaced material. the result is a progressive video with 25 full frames per second showing 2 half frames mixed together in one frame with the typical "interlaced-lines-error" or in germany we are talking about the "picket-fence-effect". it seemes that imovie does not identyfy the interlaced video automatically.

the imported videos from the camera are definately imported by imovie as interlaced video. i can check it in the quicktime player by turning on the "deinterlace"-option. quicktime playes the video deinterlaced, the "picket-fence-effect" dissapears. if i do it with a exported h.264 videofile from imovie, nothing happens when i turn the "deinterlace"-option on. the "picket-fence-effect" does not dissapear.

today i already loaded the quicktime update, but i still can not export in mpeg4/h264 interlace.

can somebody help me?? i spent already several days with exporting, searching the internet and burning dvd-rs.

thanks
reibekuchen12