How can I change my keyboard color on my unlocked iphone?

I unlocked my iphone 3g and everything works perfectly except for the fact that I have downloaded numerous keyboards but when I change them in winterboard it doesn’t change anything. Each of the keyboards I download say they are for winterboard which is why it is confusing me. Does anyone know how to change the keyboard theme so it actually changes when I SMS or email? Thanks in advance!

I’m honestly not positive that is posible. My roomie tried with no luck. This prob doesn’t help but I wanted to let you know

iOS4 Cydia KeyBoard WinterBoard Themes