Sprite creator is designed for the non artist. You are able to export single parts one by one. If you don't want to use the base I provide for example you can draw your own and just export the sprite creator sprite without the base. As for drawing your sprite from scratch, this isn't the program for that. Try something like Aesprite I highly recommend it.
There are plans for many thing for Sprite Creator. Check out the road map on the main page. Might have a feature you looking for.