In short you can't use both. The game automatically assumes that if you have a gamepad attached you won't want to use your mouse/keyboard and so ignores their input. A poor assumption in my opinion.
I'd get a http://www.walmart.com/catalog/product.do?product_id=15126816&sourceid=1500000000000003142040&ci_src=http://forums.bethsoft.com/topic/1263599-using-the-kb-mouse-xbox-controller/14110944&ci_sku=15126816 if somebody could mod in support for it. Then I'd have a ton of hotkeys & a 360 controller... the best of both worlds.
...or mod in the ability to use both KB and controller. [probably easier]
Yea maybe there is a mod. I know most games do this (basic natural support of using both)..one example off my mind is GTA IV. KB&M I'd use for shooting than when I get in a car jump to my xbox controller.