Inverting algorithms

[3dnf]

For the Square-1 I want to change one of the algorithms with 2 edge swaps in U layer, 0 edge swaps in D layer so that it is 2 edge swaps in D layer and none in the U. How would I go about doing that? The link is here: http://www.cubezone.be/square1step5.html

 

[Sa967St]

(x,y) -> (-y, -x)

 

[3dnf]

Ah, thanks a lot.