I can be wrong, and if I do, please correct me. You'll be able to inject just primitive/wrapper types and JavaBeans (getters/setters as properties and no-arg constructors), but Map isn't either of them.
With a pure ejb solution I think you'll not be able to do this. Maybe using a special implementation and CDI / JSR-330.
Feel free to ask me anything!
www.BlackBeltFactory.com/ui#!/ref=jmotta, SCJP 6, OCWCD JEE5, OCE EJB JEE6