Can you help me understand the the Execute button?

Is it possible to create a data connection to a web service in LiveCycle Designer and utilize the form in Adobe Reader?

The article Understanding the Execute Button in LiveCycle Designer details how to create a new data connection to a web service and then drag and drop the fields to your form. However, be aware that web services do not work with Adobe Reader unless you've extended the rights of the PDF using Adobe LiveCycle Reader Extensions.

To ensure your logic and connections are correct, I suggest you do all your testing with Acrobat and if it works, then you and your organization can pursue licensing Adobe LiveCycle Reader Extensions to enable the functionality to work in Adobe Reader.