Install to external USB?

[Claude Jones]

I've got a couple of flavors of Linux running on an external USB drive on my 
laptop. Both installed without major issues. I'd like to get rid of one and 
replace it with FC5t2, but, the installer doesn't give me the option of 
installing to the USB drive - it only sees the internal HD. I've tried 
searching the list, but the only references to installing to external USB 
HD's are very old. Can this be done? How can I get the installer to see SDA1? 
I do see a reference in the early boot from CD process, to installing USB 
devices and drivers, but no external USB drive is offered in the install 
page. 
-- 
Claude Jones
Bluemont, VA, USA