BeeMan,
Mama Bear is a fine soap and creator Sue Clark an artist. There is nothing wrong with grating the soap, as you do, but I have never seen the need for that — just find a bigger soap bowl.
Incidentally, from what I can tell from the photo, your lather is a wee bit too watery. Lather generally should have the consistency of meringue. Keep working the lather more, and start with less water — you can always add more water, but you can't take it out.
By the way, here is an article I wrote on Sue Clark and Mama Bear:
Lathering Up With Mama Bear