decorator-classes not scanned. (resteasy.scan.decorator does not exist)

I use Decorator-Classes as described in Resteasy-Reference-Guide 2.1 (chapter 19.1.JAXB Decorators),

However, my Decorator is totally ignored, hence it does not work.

Even not needed in jboss as because of default autoscanning, I explicitly declared autoscanning in web.xml, but it does not help - decorator classes are not regocnized.

<context-param>
<param-name>resteasy.scan</param-name>
<param-value>true</param-value>
</context-param>