Dialog window will create by means of scripts, which are ASCII text files with a format somewhat similar to .RC files. (No, it's not as complicated as you might be thinking!)
You can make some dialog window and you can use this dialog in your program because this is ActiveX.
This software is a shareware. You will be able to download and test WSH.GUI during a certain period of time, then, if it does what you need, you will have to acquire the full version from WSH.GUI publisher. The WSH.GUI 2.1 free trial version contains an installer and an uninstaller, and has a size of 317 Kilobytes.
For additional information and support request, please contact directly WSH.GUI publisher.

WSH.GUI Screenshot