HP ProLiant DL120 G5, boot from USB

Hey.

I can't get my, recently acquired, HP ProLiant DL120 G5 to boot from USB. I have tried all the USB ports it has, but nothing.
In the BIOS, the USB boot priority is set to high and I can't find a boot priority option, so can't change it to higher.

Apparently the server is not capable of booting the OS that is on it, when a USB-stick is plugged in and it falls back to netboot, which is useless, considering I havn't set up a server for this yet.

Just wondering if anyone could help me make it boot from USB.

Thanks in advance.

Well... I made it work.

My solution was to set up an TFTP server using the "Serva" program and this guide: http://www.digitalcitizen.life/how-install-any-version-windows-other-network-computers