Even right there, on the link you provided, someone is asking:

"Can i let the belly interact with a wall or a floor?

can i use softbody between figures?

would like to see some examples first, to see how well the softbody engine is implemented between:

• figures & objects (like belly punch against a wall or floor)

• figure vs figure (like a punch from figure a to figure b)"

 

So, someone is wondering about the same thing I am.