NetBSD on an external drive

how would igo about installing macppc netbsd on an external drive from either freebsd or os 10.5?

i need to do this because the odd in my powerbook g4 is broken and iwant to try netbsd on it

With a Bosch Shotgun

i have the adapter and all, i'd just like to find a way to install all the files from the iso manually

but now i'm at the library so i can search for the info myself

http://www.bsdnexus.com/NetBSD_onastick/install_guide.php
http://wiki.netbsd.se/index.php/How_to_install_NetBSD_from_an_USB_Memory_Stick

basically the same concept as installing on a usb-stick but i've only ever done that with freebsd before