no boot sequence on usb?

i have a dell insperon e1505 (2007 intel care 2 duo 2.0ghz laptop that supports SSE3). i installed a “jas” version of mac osx 10.4.8 (“Mac OS X 10.4.8 [JaS AMD Intel SSE2 SSE3 PPF1 + PPF2]” to be exact) for “test porposes.” then i want to the osx86 wiki, and fallowed the install guide to install it on a external usb drive (http://pcwizcomputer.com/software/osxusbnative.htm). i put in the disk, and install it just the way it says, excpt i installed it onto a 30gb partition on my external instead of the whole thing, and the rest of the space i left unformatted.. after a sucessfull install, i go into my BIOS and set USB drive to be the first to try to boot from. i restart my computer and it says “no boot sequence on usb drive” and then continues on to boot windows. anyone know how to fix this? also, i got a real ISO because i installed it using VMware, and it worked just to check it was good. but i want a native install. can anyone help?