Advanced book type problem

[masaydo]

I've read repeatedly that my HP 300 is a re badged NEC-1100a, and so I'm trying to set the booktype. I followed the guide in the sticky, but the option continues to be greyed out.

 

Edited December 2, 2008 by masaydo

[LIGHTNING UK!]

An NEC that old would use the RICOH command set, not the NEC one.