I did not find a way to deploy artefacts using maven directly to bintray like I did for deploying to oss-sonatype.
So I used the default parent-pom and called
mvn release:perform -Darguments=”-DaltDeploymentRepository=tmp::default::file:///tmp/repo”
and uploaded the files that were “deployed” to /tmp/repo manually.
Should take a look at https://github.com/bintray/bintray-examples/blob/master/maven-example/