The “Configure FX Automation option” is the small icon directly below the red X that closes the plug-in window. Naturally, you have to add the elastique timestretch to the chain first.
Bob
Edit: Curiously, in 9e the plugin chooser is on the track header and when you choose elastique it will allow you to ‘configure’ as mentioned above. In 10e, if you choose the plugin chooser at the event level (at the end of the audio clip) it will NOT allow you to configure it. You must choose the plugin icon in your ‘mixer’ window to get to the configure option. Hope this helps.