Error Digital Signature C# Acrobat Sdk

Hi.
I am creating an application to sign a pdf from c #.
I am currently having the following problem:

System.Runtime.InteropServices.COMException: 'Nombre desconocido. (Excepción de HRESULT: 0x80020006 (DISP_E_UNKNOWNNAME))'

This is the code:

            Type AcrobatCAcroAppType;

            AcrobatCAcroAppType = Type.GetTypeFromProgID("AcroExch.app");

            Acrobat.CAcroApp gapp = (Acrobat.CAcroApp)Activator.CreateInstance(AcrobatCAcroAppType);

            Type AcrobatPDDocType;

            AcrobatPDDocType = Type.GetTypeFromProgID("AcroExch.PDDoc");

            Acrobat.CAcroPDDoc gpddoc = (Acrobat.CAcroPDDoc)Activator.CreateInstance(AcrobatPDDocType);

            object jso;

            if (gpddoc.Open("C:\\Users\\tmuñoz\\Desktop\\PDFs Para firmar\\Thuban-Nivel 2.pdf"))

            {

                jso = gpddoc.GetJSObject();

                object[] param = new object[1];

                param[0] = "C:\\Users\\tmuñoz\\Desktop\\ThomasMuñoz.pfx";

                object con = jso.GetType().InvokeMember("SetUserDigitalIDPath",

                BindingFlags.InvokeMethod, null, jso, param);

                param[0] = "testpassword";

                con = jso.GetType().InvokeMember("SetUserPassword",

                BindingFlags.InvokeMethod, null, jso, param);

                param[0] = jso;

                con = jso.GetType().InvokeMember("AddSignature",

                BindingFlags.InvokeMethod, null, jso, param);

            }

I think the error comes from not finding these functions in the JSO object.
From what I understand these are the sdkAddSignature file.
So I guess I should integrate it into the C # project, but I do not know how to do it.