I found out about this in the FTA workbench.
The function is available in Part Design, but it's not included in any toolbar. Sounds like it's the same in the Assembly Design workbench.
So, click in the Power Input field (lower-right corner of screen) and key-in: "c:text parallel to screen" (no quotes)
If it does what you want, you can add the command to one of your Assembly Design toolbars