Bepu + Mono Exception

#exception when running under Mono
{System.MethodAccessException: Transparent method System.Collections.Generic.EqualityComparer‘ 1<BEPUphysics.ColIisionTests.Manifolds.TriangleMeshConvexContactManifold/Edge>:.cctor ()
cannot invoke private/internal method System.Collections.Generic.GenericEqualityComparer‘ 1<BEPUphysics.CollisionTests.Manifolds.TriangleMeshConvexContactManifold/Edge>:.ctor ().
at (wrapper managed-to-native) System.Reflection.MonoCMethod:InternalInvoke (System.Reflection.MonoCMethod,object,object[],System.Exception&)
at System.Reflection.MonoCMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0 }


# line that seems to be causing the exception
HashSet<Edge> blockedEdgeRegions = new HashSet<Edge>();


#the Edge struct
struct Edge : IEquatable<Edge>
{
    private int A;
    private int B;

    public Edge(int a, int b)
    {
        A = a;
        B = b;
    }

    public override int GetHashCode()
    {
        return A + B;

    }

    public bool Equals(Edge edge)
    {

        return (edge.A == A && edge.B == B) || (edge.A == B && edge.B == A);
    }
}