C# Definition:

   internal struct CRYPT_VERIFY_MESSAGE_PARA
   {
      public int cbSize;
      public uint dwMsgEncodingType;
      public int hCryptProv;
      public IntPtr pfnUnfortunatellyUnsupported;
      public IntPtr pvUnfortunatellyUnsupported;  
   }

VB Definition:

    Structure CRYPT_VERIFY_MESSAGE_PARA
        Public cbSize As Integer
        Public dwMsgEncodingType As UInt32
        Public hCryptProv As Integer
        Public pfnUnfortunatellyUnsupported As IntPtr
        Public pvUnfortunatellyUnsupported As IntPtr
    End Structure

User-Defined Field Types:

None.

Notes:

1. cbSize set to 20 bytes works well for me

2. The only supported dwMsgEncodingType is X509_ASN_ENCODING | PKCS_7_ASN_ENCODING (see constants section)