How to get Eclipse to generate MapStruct Mappers using Gradle

Is there any special copnfiguration to get eclipse to generate the Mapstruct mappers? Curently they are not being generated.

They do generate in a gradle build but I cannot get them to generate so I can use them in development.

I added this to my build.gradle:

plugins {
    id "net.ltgt.apt" version "0.10"
}
dependencies {
    compile "org.mapstruct:mapstruct-jdk8:$mapstructVersion"
    apt "org.mapstruct:mapstruct-processor:$mapstructVersion"
}

I also added the eclipse plugin for MapStruct (although I belive that this is not actually required???)

I then went Project > Properties > Java Compiler > Annotation Processing:

But .apt_generated is empty, what am I missing?

I'm using:

Eclipse: Version: Oxygen Release (4.7.0) Build id: 20170620-1800

MapStruct version 1.2.0.CR1 (also tries 1.1.0.FINAL)