...
cmd.Connection = con
cmd.CommandType = CommandType.StoredProcedure
cmd.CommandText = "usp_UDF_RTFText"
 
 With cmd
  With .Parameters
   .Add("@GrafikBereich", SqlDbType.TinyInt).Value = GrafikBereich
   .Add("@BuchungsIdent", SqlDbType.Int).Value = BuchungsIdent
   .Add("@RTFText", SqlDbType.NVarChar, 1073741823).Direction = _
     ParameterDirection.Output
   .Add("@RetValue", SqlDbType.Int).Direction = ParameterDirection.ReturnValue
 
  End With
 End With
...