Configuring COM-3 and COM-4 ports on RB-100

RB-100 comes with 4 COM ports(These are the predecessor to serial ports and are still being used on SBCs. For knowing more,see this ).Basically the linux kernel identifies only 2 COm/Serial ports.So only COM0 and COM1 work initially.To make other COM ports work you have to configure them.

The Ro-Board people provide the documentation required for configuring COM3 and COM4 ports.But they have installed Debian-5 along with GRUB-1.
Since I installed Debian-6 and it comes with GRUB-2 I had to struggle a little to configure those ports.Here is the GRUB-2 version of configuration documents:

• on terminal type /etc/default
• gedit grub or mousepad grub or vi grub
• On the 9th line or the line that contains  GRUB_CMDLINE_LINUX_DEFAULT="quiet" add 8250.nr_uarts=4 under the quotes
• now close the document
• type update-grub on terminal
• now reboot
• on typing dmesg | grep ttyS you should be able to see 4 serial ports.
• rest of setserial stuff is as usual in the documentation.

But the sad rather amusing part is that I am still not able to use COM-3 and COM-4 ports. If someone does this please tell me how to do this.