For the first question, from what I've read the BS2 Upgrade installer should be able to detect your steam version and install. Also if not done so, be sure you ran BS1 Steam at least once first before attempting to use the BS 2 Upgrade installer. I don't own the steam version of BS 1, just the boxed dvd.
For further referencing, these threads have better info then myself:
http://forums.eagle.ru/showthread.php?t=99719
http://forums.steampowered.com/forums/showthread.php?t=2911821
As for the second question, I'm not sure. The Belsimtek subforums might have the answer you're looking for.
Hope BS 2 works out and happy flying the shark. :)