The primary objectives are to demonstrate that MICARDIS® (telmisartan) is statistically superior to Diovan® (valsartan) in reducing diastolic blood pressure (DBP) following a missed dose at the end of a 6 to 8-week treatment period as measured by the 24-hour ABPM mean and to demonstrate that MICARDIS® is statistically superior to Diovan® in reducing DBP during the last 6-hours of the 24-hour dosing interval as measured by ABPM following a dose of active study medication at the end of a 6 to 8-week treatment period.