DMN Literal Expression and EJB invocation

We are struggling to figure out how to invoke an EJB from a Groovy Script in a DMN Literal Expression. There are several hints and even the Camunda doc states that it is possible, but we haven managed to get it running.
Any help from the community?

The problem was solved. Currently the only solution for this scenario is:

  • create a simple, wrapper class around the Camunda DecisionService, add your specific methods to evaluate your specific DMN (table)
  • put an instance of this wrapper class into a process variable (e.g. using a preparing BPMN Script Task)…
  • …so that you can access the process variable with their methods in your DMN Literal Expression Groovy Script