The effect of H^pm on B^pm -> tau^pm u and B^pm -> mu^pm u

The hitherto unobserved purely leptonic decays B^pm -> tau^pm u and B^pm -> mu^pm u are of much interest at current and future runs of the e+e- B factories. Such decays are sensitive to charged Higgs bosons (H^pm) at the tree-level and provide essentially model independent constraints on tanbeta/m_{H^pm}. We include the large corrections to the H^pm-ub coupling induced by virtual SUSY effects and show that the bounds on tanbeta/m_{H^pm} can be significantly weakened or strengthened.