I thought you would choose the menu entry 'knoppix' from the menu at boot time, but if you want to use 'Default' (the first entry in the boot menu) you have to edit the 'append' line of the 'Default' section. On my system I have got
Code:
label unetbootindefault
menu label Default
kernel /ubnkern
append initrd=/ubninit ramdisk_size=100000 lang=de apm=power-off nomce  libata.force=noncq hpsa.hpsa_allow_any=1 loglevel=1 tz=localtime modprobe.blacklist=rtl8192cu