m8, a l,ot of the new soundcards (xpecially USB/ Firewire) ain't that easy 2 install, most of them require u 2 go back 2 control panel/ system/ audio/ midi drivers right click and then update the drivers... after properly installed they should show up just fine in the cubase asio config, as long as yer soundcard has such drivers!
Most people don't read the install instuctions, this sort of probs is happening quite often!!
Z