I could do with a few tips too - mine always come out quite fuzzy in a car (see here http://www.360panoramics.co.uk/disco.mov (although I do keep file sizes to a max of about 1Mb. Any chance of a work flow summary?
You need to drop 1 or 2 F/Stops when shooting the "up" shot to keep the colour consistent. But all in all it is very good.
Just a point on your ISO setting. In this perticular situation there in no need for you to up the ISO because nothing is going to move in the panorama. To compansate for the light you just need a longer exsporure time. This will keep the grain down.
Markus (the original thread starter) has sharpened his pano correctly using www.ultrasharpen.com and he has also "faked" in the outside using another panorama image using Photoshop masks on all the windows. Also running ISOx Pro with you final image will help a great deal and WP Pro is a great image downsizer.