Hi yassinex. None of the Soundblasters USB seems to have any Asio driver at the moment. Due to this you could NOT play vst instruments with it with a latency lower than, say 30ms, which is not fast enough for real time. I don't think Eugene Gavrilov is thinking to support them at the moment, although he's got the last word.
Also read this:
http://www.cubase.com/forum/display_...PagePosition=1
There are some other cards that could work fine for your requirements. See Edirol:
http://www.edirol.com/products/audio.html
or Ego systems:
http://www.esi-pro.com/listProduct.php?ctgr=9
and many more. (Why not searching for USB soundcards in Google?)
Also you might try a generic Asio driver: 'Asio4all', this should work with any device, including the built in sound card of your laptop.
http://michael.tippach.bei.t-online.de/asio4all/
/Nando
PS. Don't forget the Firewire connector. There are some Firewire cards around there, some of them really sophisticated.