CaptMoto should be able to help you more on the power lead connection to your TomTom and how to tell it's taking power as he's got one.

As far as I know, the Touratech holder is just a holder for the unit itself. You still have to put your power lead into your TomTom.

With my Garmin I still have to use the original holder. The original holder bolts to the Touratech holder. The power lead screws into the original holder, not the Touratech holder.

Hope this helps.