ArcGIS SDK for WIndows Mobile 3 FeatureLayer replaced by FeatureSource. What replaced 'GetDefaultValue'

[RichardFisher]

There are several good referenced detailing what changed in the SDK such as

ArcGIS Runtime for Windows Mobile and Migrating your applications to ArcGIS for Windows Mobile 3

But there is no code example or much about what replaced the GetDefaultValue that was there in 10.0

Previously FeatureLayer was replaced by FeatureSource which has no GetDefaultValue method

object value = featureLayer.GetDefaultValue(subTypeValue, dataColumnName);