Screening At screening, eligible patients will have a baseline screening FEV1 of >/= 60 to </= 90% of predicted at least 4 hours after the last usage of a short-acting beta2-agonist. Patients will have reversible airway obstruction: a >/= 12% increase in FEV1 in comparison to baseline should be shown within 30 minutes after taking 200 µg salbutamol. If airway reversibility cannot be demonstrated during this visit, patients are eligible for re-testing. Reversible airway disease may be demonstrated at any time between screening and start of run-in period. The 2 to 4 week run-in period will start immediately after demonstration of reversible lung disease.