interlacing targa files problem


I’m trying to export (with blender 2.45) in TGA format an animation. Until I export it using PAL 16:9 setting I haven’t problem but when I try to export at 1440x1080 resolution the video editing program where I import the images see them as not interlaced. If I export in AVI RAW at 1440x1080 the AVI result interlaced. Is there some limitation on TGA files?