Tool for importing turns from table in network dataset

GraemeBrowning

The need for this arises from an issue that I have encountered at http://gis.stackexchange.com/questions/214719/using-arcpy-to-populate-turn-feature-class-for-network-analyst-by-reading-edge-I

I have successfully built a network dataset with a unique ID for every street polyline in it.  I also have a table with rows for each pair of street polyline IDs for which a turn from and onto are not permitted.

I expected it to be easy to create network dataset turn features from this table but it seems not to be possible.