Now I know nothing about cars - or vans but...
The alternator provides electrical power for the car and also charges the battery - it's driven by a belt from the engine. When the battery is not being charged the Battery (not charging) light illuminates.
The power steering requires energy to make it work - it may get this from a hydraulic (oil) pump driven by the engine - it may also be driven by a belt - it might be the same belt - your belt may have broken.
Just a guess...
Good luck...
Peccavi
February 2010