Hey there. It sounds like you want to add attributes to your foot/hand controls. To do this, simply select the object that you want to addan attribute too (your foot control, for example), then go to modify -> add attribute.. . A little GUI should pop up. Enter a name for you attribute (such as 'foot roll', for example), then set a data type and its min and max value. Then press ok, and you should see your new attribute in the channel box when you select your foot controller. You would then need to use set driven key to make you new foot roll attribute control this action for your foot. There's a tut on this site somewhere on how to use SDK, or you can find out about it in the Maya help files.
Hope this helps you a little :p