At the scenario 2 you got this :
If you want to change position or color or whatever, abort the preview, select video > filters again. The filter dialog appears, doubleclick on TextSub and you can change whatever you want. Then preview again. If you are happy, select file > Start frameserver
Is that enough ?
Try this :
http://www.dvdrhelp.com/forum/archive/t128720.html
Or select from here:
http://www.dvdrhelp.com/convert.htm