Macbook Pro (Late 2011) Bootcamp and USB boot questions

bootbootcampmacbook prousb

I have a Macbook Pro with an OWC DataDoubler drive caddy replacing the Superdrive (installed at an Apple premium reseller, when I bought it, so I can still have my warranty).

The main drive slot has an SSD, and the Superdrive slot has the original 750GB hard drive. It all works great, and I have Lion installed on the SSD – blazing fast 🙂 I also have the Superdrive on an external USB enclosure, also works fine.

Problem is, I would like to install Windows on the secondary hard disk. I tried using Bootcamp, but it wouldn't originally let me create the USB install disk (I've overcome that with the tip described here) but even if I use the USB Superdrive, I always get the "Boot device not found, press any key" message.

So, my question is: what am I doing wrong? Is it possible to install Windows on a secondary hard drive? How can I avoid the "Boot device not found…" message?

Thanks for any help!