BitLocker - Booting from a BitLocked USB key

My hard drive is encrypted by BitLocker. I changed the admin settings to require a USB key inserted into my computer to logon. That works fine. I want to know if I can BitLock my USB (the one that is used to boot my BitLocked computer) because I have other files on there that I want to secure. I'm encrypting right now and am just wondering. I'll test it out when my encryption ends in about 2 hours.

It doesn't work. You cannot boot a computer that requires a key stored on a USB that has been BitLocked. You can still store any data on your USB and still boot from it, but you cannot encrypt the data you put on there (key on USB is encrypted and impossible to reveal).