PromptKeywordOptions and underscore

Hi folks

My target was to do a little routine that creates layouts for the views and sets page setups for these layouts. Name of the page setup is asked from the user before making the layouts and I try to use

PromptKeywordOptions so that user can only select existing page setups.

And here comes the problem. If there is underscore (_) or more in the page setup's name and I type that name, I get error "Invalid option keyword." in the command line. When I messed with page setup manager and tried to rename setups with special characters, I got the following message: "The following characters are not supported: \ / ? " : ; * | , = `". but there are no mention about the underscore.

How do I select the name with underscore or do I have to replace all underscores from my page setup names?

Here is the routine for selecting page setup:

using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using System;
using System.Collections.Generic;

namespace CAD
{
   public class PageSetupSelector
   {
       Document doc;
           
       [CommandMethod("SelectPageSetup")]
       public void SelectPageSetup()
       {
           doc = Application.DocumentManager.MdiActiveDocument;
           Database db = doc.Database;

           using (Transaction trans = db.TransactionManager.StartTransaction())
           {
               DBDictionary pageSetups = (DBDictionary)trans.GetObject(db.PlotSettingsDictionaryId, OpenMode.ForRead);

               List<string> setupNames = new List<string>();
               doc.Editor.WriteMessage("\nPage setups:");
               foreach (DBDictionaryEntry entry in pageSetups)
               {
                   doc.Editor.WriteMessage("\n {0}", entry.Key);
                   setupNames.Add(entry.Key);
               }
               
               if (pageSetups.Count > 0) {
                   string question = "\nSelect pagesetup: ";
                   string answer = AskKeywordFromUser(question, setupNames.ToArray(), setupNames[0]);
                   doc.Editor.WriteMessage("\nSelected setup: {0} ", answer);
               }
               trans.Abort();
           }
       }        
       
       protected string AskKeywordFromUser(string question, string[] words, string defaultWord)
       {
           PromptKeywordOptions pko = new PromptKeywordOptions("");
           pko.Message = question;
           pko.AllowNone = false;
           foreach (string word in words) {
               pko.Keywords.Add(word);
           }
           pko.Keywords.Default = defaultWord;

           PromptResult pr = doc.Editor.GetKeywords(pko);
           if (pr.Status != PromptStatus.OK) {
               return String.Empty;
           }
           return pr.StringResult;
       }        
   }
}

And here is the output from the command line:

Page setups:
test-A3
test_A3
Select pagesetup [test-A3/test_A3] <test-A3>: test_A3
Invalid option keyword.
Select pagesetup [test-A3/test_A3] <test-A3>: "test_A3"
Invalid option keyword.
Select pagesetup [test-A3/test_A3] <test-A3>: 'test_A3'
Invalid option keyword.
Select pagesetup [test-A3/test_A3] <test-A3>:
Selected setup: test-A3

I found the solution from other site http://forums.autodesk.com/t5/net/getstring-with-keywords-fatal-error/td-p/3373735

Solution was to set PromptKeywordOptions.AllowArbitraryInput to true.

protected string AskKeywordFromUser(string question, string[] words, string defaultWord)
{
   PromptKeywordOptions pko = new PromptKeywordOptions("");
   pko.Message = question;
   pko.AllowNone = false;
   foreach (string word in words) {
       pko.Keywords.Add(word);
   }
   pko.Keywords.Default = defaultWord;
   [color=red]pko.AllowArbitraryInput = true;[/color]

   PromptResult pr = doc.Editor.GetKeywords(pko);
   if (pr.Status != PromptStatus.OK) {
       return String.Empty;
   }
   return pr.StringResult;
}