Englarge an Edit control's Undo queue

I would be thankful for any scripts that can enlarge the undo queue
Or any good idea for a strategy for implementing undo's and redo's.

I found this script on the web but I do use AutoIt3 ...

		case WM_CHAR:
			switch (wParam)
			{
				case 0x08:
					// Process a backspace.
					break;
				case 0x0A:
					// Process a linefeed.
					break;
				case 0x1B:
					// Process an escape.
					break;
				case 0x09:
					// Process a tab.
					break;
				case 0x0D:
					// Process a carriage return.
					break;
				default:
					// Process displayable characters.
					break;
			}

It seems so far that this is a kind of a difficult project.