Why don't you just upgrade your server to WildFly 8+ best if 10, which comes with resteasy 3 and jackson2 as default provider
For a soft migration, we would like to have a version of our application that runs on both jboss and wf10. Would it be possible to make jboss 7 use resteasy-jackson2-provider by only fitting the pom.xml? Either we would have to ship our application directly with the jackson2-provider (is that possible?) or ... somehow ecipse would have to deploy it as a jboss7-module.