Yup, I know! Tried various things. The included drivers (rtl8180 which state they are for PCI, and rtl8187 for USB) do _not_ work with the mentioned chip (RTL8188CUS).
Somebody attacked this issue with raspberryPi already. Changelog, Introduction: http://dl.dropbox.com/u/80256631/install-rtl8188cus.txt and the script is here: http://dl.dropbox.com/u/80256631/install-rtl8188cus-latest.sh.