How to attach the Kotlin library sources?

However i can't fix android-library source attaching (aar)

for example i can’t see sources for http://search.maven.org/#artifactdetails%7Cio.reactivex%7Crxandroid%7C1.0.1%7Caar
and also for my own android libraries.

task androidSourcesJar(type: Jar) {
    classifier = 'sources'
    from android.sourceSets.main.java.sourceFiles
}

sources are generated and i can see them under .jar, but can't get it to work in AS