Than thank you for writing.
@Karen, thank you for providing relevant forum post.
@Javier, as far as I can understand from the provided information you want to change the appointment edit form? If so, you can read the forum post provided by @Karen and the following help article: Adding a custom field to the EditAppointment dialog
which will also show you how to add custom properties to your appointment.
Let me know, in case you have other questions.
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.