Yeah, there should be a pppoe dialer in the Overclockix section of the menu. Or you could use a router which has PPPoE capability.
Create Persistent Home is also in the Overclockix section of the menu. You need about 32mb minimum. And be very careful your don't format your whole partition to EXT3 (unless you want to), but just create an ext3 image instead.
I'm not sure if the pppoe info will get saved in persistent home or not.
To use persistent hom in the 3.4 iso, you need to boot with the code-
knoppix home=scan lang=us + any other codes you prefer
The = key is shift + 0 on the german keybvoard layout. (I may get this corrected this weekend and put a new iso out)