User544512917 posted
In answer to your questions:
1) If you want to change the text that appears on a UserControl, go into the .ascx file where it is defined. A template by definition does not allow the addition of text outside of a subcontrol.
[EDIT: In this case, the control is a server-side control defined in a .cs file. So the modification to the displayed text would need to go in that file. There is no designer available for such a control.]
2) Item seems to be what the designer calls the default template.
3) There does not seem to be any way to databind controls from the designer.