[Grml] serial console with grml_2011.12-rc1

I can't get a serial console with grml_2011.12-rc1. I think (can't be sure because I'm blind) I am typing this:

grml serial console=ttyS0,19200n8

If I boot my machine into linux off the hard drive, I get my serial console. So I know there is nothing wrong with my null modem cable or my terminal emulator. But with grml, I do not get a prompt of any type. From the terminal side, it looks like there's no getty on the other side.