"Screen Energy Saving" (in KDE) - how to trigger command when entering and exiting such mode?

Question

I have two commands:

• one I'd like to execute when computer enters "Screen Energy Saving" mode,
• another when it exists this state.

How to trigger those commands depending on "Screen Energy Saving" ?

(I use KDE 4.13.0, and above is feature of KDE's "Power Management")