Incidentally, i was asked in pm how i did a cut so evenly, and scribed the lines for the door trim.
I used a scribing tool made by Trumpeter. Cost about $5, and will scribe a nice neat square line, not quite 1mm thick. Several passes will basically cut through the plastic leaving a nice neat line.
http://www.hobbyeasy.com/en/data/36077.html
There are several others as well, tip and handle design, but this one does the job just fine for me.