Accessing label rotation option to keep label upright using Maplex engine from ArcObjects

[MarkMcCall1]

In ArcGIS for Desktop (10.2.2) using the Maplex labelling engine, layers can be configured to NOT flip automatically.  This option appears in the Label Rotation Dialog.  I have been unsuccessful finding the value for a given layer from within ArcObjects.  I have searched for the property on MaplexLabelEngineLayerProperties and on its OverposterLayerProperties.  I've successfully located all of the other label position/rotation properties available on the Label Rotation dialog, except for the setting to Keep Label Upright.  Any assistance directing me to where this property is exposed is greatly appreciated.

[CraigWilliams]

This property is IMaplexRotationProperties::AlignLabelToAngle which is on the MaplexRotationProperties object accessible via IMaplexOverposterLayerProperties::RotationProperties.

Craig