Yes, atv, version 2 was not very successful indeed. Nonetheless it has code to read and write postgres/postgis tables.
It should be straight forward to create and implement
interface IUpdatableProvider : IProvider
IUpdateableProvider Create(FeatureDataTable table, string schema, string name);
You can find the code in the v2 trunk. You might want to consider using NetTopologySuite.IO.PostGis project for writing the geometries, as that way you don't need the conversion to and from Well-known-binary.