Prot# 211-10/FOS530: 12-Month Extension to: Rndmzd, Dbl-Blnd, Dbl-Dmmy, Prll-Grp, Mltcntr Study to Evaluate & Compare Effects of 1x Wkly Alendronate & Risedronate on Bone Mineral Density in Postmenopausal Women w/Osteoporosis (FACT - OSAMAX® ACTONAL® Comp