The easiest way to add special keys is by using the Edit keyboard type window.
- Add a key to the on-screen keyboard in the Edit keyboard type window. You can use unassigned keys defined by a hexadecimal code (for instance, 00D9).
- Select the key and press the Action... button. In the new Keyboard Shortcuts Settings window, assign the Paste text action to that key. Enter your text (in this case, ".com") into the Text field. Set the Show text on the on-screen keyboard checkbox under the Text field as desired.
After configuring these settings, save them and close the window.