I went a bit further. In fact, I think the parameters which as classes
should be interfaces as well. So I get my hand durty and did it...
However, the VB code does not get the object as prepared in managed coded.

Any idea?

Code snippet:
=========

   [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
   [Guid("1930F351-E6B3-4706-8784-562F7B541340")]
   public interface _UFSStatusAccess
   {

       TerminationCode GetTransmissionMode (bool UseCaching, out TransModes
UFSMode, out string strErrDescr);
    }

   [Serializable]
   public enum TerminationCode:int
   {
       eOK          = 0,
       eErrXXX   = 1,
       eErrNoConfirmation      = 8901,
       eErrInitNotSuccessfull  = 8902,
       eWngXXX                 = 189000,
       eWngNoCommunication     = 189001,
       eInfXXX                 = 28900,
       eDBGXXX                 = 38900
   }

   [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
   [Guid("B758299E-A024-40b3-9740-A35CA7A9D378")]
   public interface ITransModes
   {
       /// <summary>Is UFS currently online?</summary>
       bool Online {get; set;}
       /// <summary>Is UFS currently in memory mode?</summary>
       bool MemoryMode {get; set;}
   }

Then I have classes that implements the IF:

   [Serializable]
   public class TransModes : ITransModes
   {
       public TransModes() {}

       public  bool Online {get{return m_Online;} set{m_Online = value;}}
       public bool MemoryMode {get{return m_MemoryMode;} set{m_MemoryMode =
value;}}

       // Class members that will hold the states
       public bool m_Online;
       public bool m_MemoryMode;
   }

      public TerminationCode GetTransmissionMode (bool UseCaching, out
ITransModes UFSTransMode, out string strErrDescr)
       {
           try
           {
               UFSTransMode = new TransModes();
               TransModes UFSTransModeEx = (TransModes)UFSTransMode;

               return m_UFS.GetTransmissionMode(UseCaching, out
UFSTransModeEx, out strErrDescr);
  --> at this point the UFSTransModeEx has valid values.....

           }
           catch (Exception ex)
           {
               UFSTransMode = new TransModes();
               strErrDescr = "Error occured while trying to get UFS
transmission modes. Err: " + ex.Message;
               return TerminationCode.eErrXXX;
           }
       }

VB PART:
========

Private UFSStatus As New UFSStatusProvider.UFSStatusAccess

Private Sub Test_Click()

Dim errMsg As String
Dim stat As UFSStatusProvider.TerminationCode
Dim Mode As UFSStatusProvider.ITransModes

Set Mode = CreateObject("UFSStatusProvider.TransModes")

stat = TerminationCode_eErrXXX
Mode.MemoryMode = True
Mode.Online = False
stat = TerminationCode_eErrXXX
stat = UFSStatus.GetTransmissionMode(True, Mode, errMsg)

'---------------> stat and errMsg are returned ok... Mode not :-((

End Sub

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