As defined in Microsoft help the duplex property can be set as follows.
VbPRDPSimplex 1 Single-sided printing with the current orientation setting.
VbPRDPHorizontal 2 Double-sided printing using a horizontal page turn.
VbPRDPVertical 3 Double-sided printing using a vertical page turn.
Does anyone know how to check whether the current printer is capable of duplex printing.
