I dyed mine with RIT dye, specifically the powder kind. Mix it with boiling water, put the mixture in a shoe-box sized container, let the soles sit in the dye, used a brush to paint coats of the dye onto the suede.
I don't think you can dye anything white, you'd probably be better off with spray paint. In which case make sure you use flat, not gloss or semi gloss or anything like that.