Dr. Silverman's book Upside Down Brilliance has some techniques in it for teaching math. And there might be something on her Website:
http://www.visualspatial.com/Articles/articles.htm. She recommends using games, charts, drawings, colors, etc.
Not sure what you mean by teaching math backwards.. VSLs like to see the big picture first so they learn whole to parts. Especially for a 5 year old, math manipulatives are a concrete way to teach abstract. I have used Miquon wooden rods [http://www.keypress.com/x6253.xml] with my sons. I also like three corner cards [http://www.amazon.com/Three-Corner-Flash-Cards-Addition-Subtraction/dp/B0006HXTY6] that would have 5, 3 and 8 on the card to teach addition and subtraction. Singapore math [singaporemath.com] uses model method and that seems to work for my VSL son.
