Global task listener with spring-boot

Hello,

I am new to Camunda and I am trying to implement a website based on it.
I need to have a global task listener (and execution as well) to achieve real-time with websockets.

But I don’t know how to override the task listener (as there : https://docs.camunda.org/manual/7.5/user-guide/process-applications/process-application-event-listeners/) because I can’t extend the class ServletProcessApplication in my spring-boot application. I tried something with bpm-reactor as well :
(nb: it is kotlin)

open class Config : ProcessEnginePlugin {
@Bean
override fun preInit(p0: ProcessEngineConfigurationImpl?) {
    println("access to configuration") //never called - can't update my config somehow
}

override fun postProcessEngineBuild(p0: ProcessEngine?) {
}

override fun postInit(p0: ProcessEngineConfigurationImpl?) {
}

}

Thank you in advance.