Yeah, according to Eric there is no root access to the device with the zenMiner software loaded onto the Pi so the username/password are pretty useless.
Login is root/gawminers.
There's a couple of python scripts running as daemons that run that spawn the cgminer and communicate with zenminers.com, you need to disable start01 and startserver if you don't want to use their stuff.
initctl stop start01
initctl stop startserver
Now you can run screen -R to open the existing cgminer instance. CTRL-C to kill it, now start a new screen and run a new cgminer with whatever options you want. It's basically the same as running your own Pi now but with a pre-installed OS and cgminer supporting the GAWminers.