Hi! I think that this can be useful for someone here at ESRI Forums... 

This is a class, dependent from GeoAPI and NetTopologySuite, that can make any convertion between IGeometry and WKT/WKB... 

For the tests that I've made this is working... please let-me now if not... 

using System;
using System.Collections.Generic;
using System.Text;
using GisSharpBlog.NetTopologySuite.IO;
using ESRI.ArcGIS.Geometry;namespace Utils
{/// <summary>/// This class is used to convert a GeoAPI Geometry to ESRI and vice-versa./// It can also convert a ESRI Geometry to WKB/WKT and vice-versa./// </summary>public static class Converters{public static byte[] ConvertGeometryToWKB(IGeometry geometry){IWkb wkb = geometry as IWkb;ITopologicalOperator oper = geometry as ITopologicalOperator;oper.Simplify();IGeometryFactory3 factory = new GeometryEnvironment() as IGeometryFactory3;byte[] b = factory.CreateWkbVariantFromGeometry(geometry) as byte[];return b;}public static byte[] ConvertWKTToWKB(string wkt){WKBWriter writer = new WKBWriter();WKTReader reader = new WKTReader();return writer.Write(reader.Read(wkt));}public static string ConvertWKBToWKT(byte[] wkb){WKTWriter writer = new WKTWriter();WKBReader reader = new WKBReader();return writer.Write(reader.Read(wkb));}public static string ConvertGeometryToWKT(IGeometry geometry){byte[] b = ConvertGeometryToWKB(geometry);WKBReader reader = new WKBReader();GeoAPI.Geometries.IGeometry g = reader.Read(b);WKTWriter writer = new WKTWriter();return writer.Write(g);}public static IGeometry ConvertWKTToGeometry(string wkt){byte[] wkb = ConvertWKTToWKB(wkt);return ConvertWKBToGeometry(wkb);}public static IGeometry ConvertWKBToGeometry(byte[] wkb){IGeometry geom;int countin = wkb.GetLength(0);IGeometryFactory3 factory = new GeometryEnvironment() as IGeometryFactory3;factory.CreateGeometryFromWkbVariant(wkb, out geom, out countin);return geom;}public static IGeometry ConvertGeoAPIToESRI(GeoAPI.Geometries.IGeometry geometry){WKBWriter writer = new WKBWriter();byte[] bytes = writer.Write(geometry);return ConvertWKBToGeometry(bytes);}public static GeoAPI.Geometries.IGeometry ConvertESRIToGeoAPI(IGeometry geometry){byte[] wkb = ConvertGeometryToWKB(geometry);WKBReader reader = new WKBReader();return reader.Read(wkb);}}
}