usb boot manager with no usb bios support

[magnumopus]

Hello,
my computer has no usb bios support. It can boot just from floppy or cd-rom.

I have an external usb HD, and I would like to install there Gentoo.

What boot manager can I use, which can see the usb external HDs? Or how can I prepare a boot floppy and/or which can see the external usb HD, and boot it? (N.B.: I don't want to load the kernel from a floppy/cdrom; I want to boot the kernel/entire system which resides on the external HD).

I'd like to easy be able to move my usb external HD to another computer, so I need a boot loader on a floppy and optionally on a cdrom also. Easy transportability.

Can you give me some suggestions? I was thinking about a DOS floppy with usb support, and then loadlin, but I'm not sure if it's the best way. I accept also commercial solutions. The best fit is a ready boot manager with usb support.