16:9 and 4:3 no displaying correctly! Help!

[CubaseMat]

Hey, I REALLY need help, been through a 6 hour encoding process 5 times and I am really growing tired of it!

I have a 3.5 hour show which I am trying to burn to a DL DVD. The show was originally filmed in 16:9 but I had captured it as 4:3 so now it is squashed. So I chose the option to "Stretch for widescreen displays" in the processing options of the video and checked how it would look using the preview window in the 'Edit' section of the program. It looks perfect at 16:9 (stretched back to proper resolution) and it also letterboxes when in 4:3 mode which is perfect! (have no idea how it can do that… but read on…)

I also have a 16:9 video (proper 16:9 filmed in 16:9), which I want to pillar-box on 4:3 and keep the ratio on 16:9 displays... but even though when I choose ''maintain aspect ratio" in processing options (I can only change the videos “on widescreen displays” settings as the other are greyed out and it thinks it is a 4:3 video for some reason), but it looks fine when I switch between 4:3 and 16:9 mode in the ‘edit’ preview window, when I go to the ‘finish’ preview window, it squashes to a pillarbox 4:3 on a 16:9 display!!

So for some reason my 4:3 footage which should be 16:9 displays perfectly well in the final preview when at 16:9, but my 16:9 footage displayed at 16:9 stretches! Which means the 'edit' preview window and the 'finish' preview window are giving me different results!!!!!! Can I se my 'finish' preview window to use 4:3 so I can see what it comes up with??

Also, because the 'finish' preview window and the 'edit' preview window are telling me something different I fear that even though my 16:9 squashed to 4:3 video looks great, I fear it will not work when I burn the DVD... is there any way to flag my squashed 4:3 video into 16:9 so that it will display properly in a 16:9 display and letterbox on a 4:3 display?

I really need some help please!

Thank you!