Interfaces/zugferd: fix parameter error which leads to falsely allowing mails with two zugferd invoices

Interfaces/ZUGFeRDInterface.vb

@@ -220,7 +220,7 @@ Public Class ZUGFeRDInterface
         Try
             Dim oNavigator As XPathNavigator = pDocument.Item2.CreateNavigator()
             Dim oReader As XmlReader
-            Dim oResult = Nothing
+            Dim oObject As Object = Nothing
 
             Dim oAllowedTypes As New List(Of Type)
 
@@ -242,7 +242,7 @@ Public Class ZUGFeRDInterface
 
                 Try
                     oReader = oNavigator.ReadSubtree()
-                    oResult = oSerializer.Deserialize(oReader)
+                    oObject = oSerializer.Deserialize(oReader)
                     _logger.Debug("Serializing with type [{0}] succeeded", oType.FullName)
                     Exit For
                 Catch ex As Exception
@@ -252,11 +252,11 @@ Public Class ZUGFeRDInterface
                 End Try
             Next
 
-            If oResult Is Nothing Then
+            If oObject Is Nothing Then
                 Throw New ApplicationException("No Types matched the given document. Document could not be serialized.")
             End If
 
-            Return oResult
+            Return New Tuple(Of String, Object)(pDocument.Item1, oObject)
 
         Catch ex As Exception
             _logger.Error(ex)