It can't be a part of official Wine due to license limitations. You can find a separate source for the wine-asio driver here: http://sourceforge.net/projects/wineasio
Firstly, I want to thank you for finding some way for Cubase Studio 4.1.2 to work with Wine. I currently own Cubase 4 and it is the only thing keeping me from moving to Ubuntu. If I can get Cubase 4.5.2 to work with my Audiophile 2496 on Ubuntu (and it work well), I can finally ditch Vista.
Reulle, since you've tested Cubase Studio 4.1.2 successfully, have you run into any further issues, or any issues from updating? I had also read that people were worried about the syncsoft protection key not working with Linux - did you find this to be a problem as well? I also know when newer versions of Wine comes out, I'll stop seeing any posts about particular software - sometimes this means that there are no longer issues (which I'm hoping).
I appreciate the time you spent in testing Cubase - I can't tell you how frustrated I am with my current setup on Vista.
- Xal
EDIT: I plan on doing some tests later tonight, I'm not nearly as technical of a user as Reulle but I'm hoping I can update Wine's db listing with Cubase 4.5.2.