VBA Migration to C # - V10 (CustomerID)

I needed help in validating a small customization of VBA for C #. In this case does CDU_CabVar1 not get the value of the CabecDoc.ModoPag field? The messages appear with correct value but the field does not get the value when the client is identified.

using System.Text;
using System.Threading.Tasks;
using Primavera.Extensibility.BusinessEntities.ExtensibilityService.EventArgs;
using Primavera.Extensibility.Sales.Editors;
using Primavera.Extensibility.BusinessEntities;
using StdPlatBS100;
using VndBE100;
using BasBE100;
using StdBE100;
using VndBS100;

namespace Primavera.Logistics.Extensibility
{
    public class SalesEditor : EditorVendas
    {
        public override void ClienteIdentificado(string Cliente, ref bool Cancel, ExtensibilityEventArgs e)
        {
            PSO.Dialogos.MostraAviso("ModoPag: " + this.DocumentoVenda.ModoPag);

            this.DocumentoVenda.CamposUtil["CDU_CabVar1"].Valor = this.DocumentoVenda.ModoPag;

            PSO.Dialogos.MostraAviso("Valor do campo CABVAR1: " + this.DocumentoVenda.CamposUtil["CDU_CabVar1"].Valor);

            base.ClienteIdentificado(Cliente, ref Cancel, e);
        }
    }
}