ScalaStyle custom rules

I'm trying to get ScalaStyle inspections working with some custom rules but IntelliJ does not seems to pick them up. Built-ins rules are correctly reported in the IDE, custom rules are just ignored.

Those rules are correctly checked from SBT: running "scalastyle" from the SBT shell prints them out as expected.

I'm guessing maybe the Scala plugin does not have the jar with the implementation of those rules in its classpath, thus ignoring them. I can't seem to find another explanation since the inspection implementation code seems straightforward and should be able to pick up and report my rules like any other.

Is there a way to add custom rules implementation to the Scala plugin classpath or is this an unsupported feature of scalastyle in IntelliJ?