Request/Response from .NET webservice client (VB 4.5) vs Javax-ws Apache hosted service

I created a WebService in VisualStudio Professional (.NET 2.0) and I migrated it to VS 2019 (.NET 4.7.2) I set authentication to Basic as required by the service and I can connect to the configure endpoint, which as a response to DirAsync request issues an error "Il contenuto della risposta rilevato dal client è di tipo 'multipart/related; boundary="MIMEBoundaryurn_uuid_E39B3B6C2A52BD11C21604500039235"; type="application/xop+xml" Please note that to issue a put (the mai operation) I have to insert in the request a multipart/related message as well, namely the fille name and an array of byte as the conversion from an xml file, signed to become a .p7m signed file Ho creato un WebService con VisualStudio 2012 Professional (.NET 2.0) e l'ho migrato in VisualStudio2019 Community, usando .NET 4.7.2. Ho impostato l'autenticazione a Basic come richiesto dal servizio e mi connetto all'endpoint, che alla richiesta DirAsync risponde con un errore "Il contenuto della risposta rilevato dal client è di tipo 'multipart/related; boundary="MIMEBoundaryurn_uuid_E39B3B6C2A52BD11C21604500039235"; type="application/xop+xml". Da notare che per effettuare una put devo inviare nel file wsdl un array di Bytes a seguire del nome del file, credo in formato multipart/related come la risposta. =====================relevant vb code================================== Option Strict Off Option Explicit On Imports [login to view URL] Imports [login to view URL] Imports [login to view URL] Imports [login to view URL] Friend Class MENU_Renamed Inherits [login to view URL] Dim WithEvents wsFtp As [login to view URL] ... ... ... Private Sub btnTest_Click(sender As Object, e As EventArgs) Handles [login to view URL] Const _tls12 As SslProtocols = [login to view URL] Const Tls12 As SecurityProtocolType = CType(_tls12, SecurityProtocolType) [login to view URL] = Tls12 wsFtp = New [login to view URL] Dim mycredentialCache As CredentialCache = New CredentialCache() Dim credentials As NetworkCredential = New NetworkCredential("LogId", "Password") [login to view URL](New Uri("[login to view URL]"), "Basic", credentials) [login to view URL] = mycredentialCache [login to view URL]("?") End Sub Private Sub wsFtp_dirCompleted(sender As Object, e As [login to view URL]) Handles [login to view URL] Try Dim res = [login to view URL] Dim r = res Catch ex As Exception Dim err As String = [login to view URL] If [login to view URL] IsNot Nothing Then err += vbCrLf + [login to view URL] End Try End Sub