Microsoft Office applications do not run scripts automatically when some event occurs in the application — there are no events.

Thus you cannot "intercept" events such as button-clicking or selecting menu items. This is intentional on the part of the application developers as a security measure — they do not want to allow the possibility of malicious interference. So that means that you cannot have a script run automatically when you click the Send Now button. You have likely discovered that the so-called "Outgoing Rules" are really "Outgone Rules." They run only on the sent message after it has been sent, which is too late to alter anything in it.

However, there is a trick to it that works almost every time: run a script every one minute from a repeating schedule. The script can check for all sorts of things, in particular whether there is a new draft window (new message window) in the front. If there is not, the script will do nothing, but if there is, the script can do whatever you need and check for other conditions. Since it should almost always take you more than a minute to write a message (and the average will actually be 30 seconds before the next schedule run), it can catch your message before you've finished writing it and add what you need. The scripts in the next topic take advantage of that fact. For more information, see Attach a vCard.