diff --git a/Interfaces/ZUGFeRDInterface.vb b/Interfaces/ZUGFeRDInterface.vb
index 9af7367f..4bea907a 100644
--- a/Interfaces/ZUGFeRDInterface.vb
+++ b/Interfaces/ZUGFeRDInterface.vb
@@ -209,10 +209,9 @@ Public Class ZUGFeRDInterface
             Catch ex As Exception
                 _logger.Error(ex)
             End Try
-        Else
-            Return Nothing
         End If
 
+        Return Nothing
     End Function
 
     Public Function GetSerializedXMLContentFromFile(oFileInfo As FileInfo) As ZugferdResult
diff --git a/Interfaces/ZUGFeRDInterface/PropertyValues.vb b/Interfaces/ZUGFeRDInterface/PropertyValues.vb
index 7b2426c9..a7a11d4e 100644
--- a/Interfaces/ZUGFeRDInterface/PropertyValues.vb
+++ b/Interfaces/ZUGFeRDInterface/PropertyValues.vb
@@ -3,6 +3,7 @@ Imports System.Reflection
 Imports System.Text.RegularExpressions
 Imports System.Xml
 Imports DigitalData.Modules.Logging
+Imports GdPicture.Internal.MSOfficeBinary.translator.Spreadsheet.XlsFileFormat.Records
 Imports GdPicture.Internal.MSOfficeBinary.translator.Tools
 
 Public Class PropertyValues
@@ -225,9 +226,15 @@ Public Class PropertyValues
 
                             ' This should hopefully show config errors
                             If TypeOf oPropertyValue Is List(Of Object) Then
-                                _logger.Warn("Item with specification [{0}] may be configured incorrectly", oTableColumn)
+                                _logger.Warn("Item [{0}] may be configured incorrectly", oTableColumn)
                                 oPropertyValue = Nothing
                             End If
+
+                            If IsComplexeObject(oPropertyValue) = True Then
+                                _logger.Debug("Item Value [{0}] is complexe. cant be used.", oTableColumn)
+                                oPropertyValue = Nothing
+                            End If
+
                     End Select
                 End If
             Catch ex As Exception
@@ -593,8 +600,21 @@ Public Class PropertyValues
                     firstElement = oList.FirstOrDefault()
                     If firstElement IsNot Nothing AndAlso IsArray(firstElement) Then
 
-                        ' Attachments sind Byte-Arrays und müssen umgewandelt werden
-                        Return Convert.ToBase64String(firstElement)
+                        Dim oStr As String
+                        ' Array behandeln -> erstes Element nehmen
+                        If TypeOf firstElement Is String() Then
+                            Dim arr As String() = CType(firstElement, String())
+                            oStr = If(arr.Length > 0, arr(0), String.Empty)
+                        Else
+                            oStr = firstElement.ToString()
+                        End If
+
+                        If IsBase64String(oStr) Then
+                            ' Attachments sind Byte-Arrays und müssen umgewandelt werden
+                            Return Convert.ToBase64String(firstElement)
+                        Else
+                            Return oStr
+                        End If
 
                     Else
                         Return DoGetFinalPropValue(oList.First())
@@ -636,4 +656,40 @@ Public Class PropertyValues
         Return Regex.IsMatch(Prop, _indexPattern)
     End Function
 
+    Private Function IsComplexeObject(obj As Object) As Boolean
+        If obj Is Nothing Then Return False
+
+        Dim t As Type = obj.GetType()
+
+        ' Einfache Typen ausschließen
+        If t.IsPrimitive OrElse
+           t.IsEnum OrElse
+           t Is GetType(String) OrElse
+           t Is GetType(Decimal) OrElse
+           t Is GetType(DateTime) Then
+            Return False
+        End If
+
+        ' Wenn es öffentliche Properties hat, ist es "komplex"
+        Return t.GetProperties().Length > 0 OrElse t.IsClass
+    End Function
+
+    Function IsBase64String(str As String) As Boolean
+        If String.IsNullOrEmpty(str) Then Return False
+
+        ' Base64 hat bestimmte Zeichen und meist Länge Vielfaches von 4
+        If str.Length Mod 4 <> 0 Then Return False
+
+        ' Regex-Check für gültige Base64-Zeichen
+        If Not System.Text.RegularExpressions.Regex.IsMatch(str, "^[A-Za-z0-9+/]*={0,2}$") Then
+            Return False
+        End If
+
+        Try
+            Dim bytes As Byte() = Convert.FromBase64String(str)
+            Return True
+        Catch ex As FormatException
+            Return False
+        End Try
+    End Function
 End Class