Installing via serial console

I'm stuck - when I boot the machine and hit 5 on the keyboard, all I get is an SP login. Can someone give me some tips on how to get to the install via the serial port?

may want to put down what type of system you have
when the systems startup there are 2 diffrent menus you can get

on power-on
first one Power menu ( CPU en abel disable menu ) mostly for CE

The next menu should be the SMS menu once the system beeps and before it starts booting O/S
( press F1 or 1 or esc+1 deend on the system )
this is used for setting up boot and install etc

The system is a P5.

After a good 6 hours of ripping my hair out, I finally got it. I think when the system was originally installed it was intalled with a head and a keyboard. I had to go into the ASMI (is that what it's called?), and reset to factory configuration. I then powered on, and got the banner screen where I could hit 1 to get to SMS settings.