I have the same situation : I have a 24v RGBW LED Strip that needs a 240V -> 24V transformer. The strip is controlled via a Fibaro RGBW module, however, I also wanted to use a wall switch to turn on/off the LED Strip. Both transformer and RGBW module are located in a ceiling void.
As the RGBW controller needs 0-10V switches to control it directly and cannot use 240v switches, I decided to simply use a 240v wall switch (using a spare output from Fibaro Double Switch 2) to power on/off the transformer instead.
However, if you don't keep the RGBW controller powered permanently, then it looses the settings (like last brightness, last colour etc).
My hack work-around is to use PLEG and monitor the Double Switch 2 output, ensuring this always in an on-state, and programmatically turn on/off the LED strip.
The downside to this means that the transformer does use power 24/7 though. In an idle state, on but RGBW strip off, Vera reports 0.8W. Whilst this is not ideal, it gets the WAF from having the LED strip turn on/off via a wall switch!