I'll be writing this post in english in case any googlers stumble upon this.
I had problems getting my Roland UA-25 usb audio interface to work with both Linux Mint and Ubuntu 9.04.
After some serious googling and swearing I found this link:
http://meandubuntu.wordpress.com/2008/01/30/ubuntu-and-studio-work-pt-1-foundations/#more-46 which worked really well.
Now I have sound which is really good for my sanity, so thx Me and U(buntu)!