so it's possible to inject them via @Inject.
however, sometimes you need to use other annotations like @EJB or @Autowired.
in an ee-server ee-annotations like @EJB work out-of-the-box. however, in case of a manual setup e.g. in combination with a servlet-container like tomcat, you might not be able to inject references to remote-ejbs. in any case you can't use non-ee annotations like @Autowired in cdi-beans out-of-the-box.
as mentioned in previous posts apache openwebbeans is very flexible.
owb is based on a simple plugin architecture which allows to customize parts easily.
some years ago i published an add-on for owb which allows to inject remote-ejbs via @EJB into cdi-beans in non-ee environments.
the add-on injects references resolved by a custom ejb-resolver into injection-points annotated with @EJB.
with the same approach it's possible to use 3rd party annotations in cdi-beans.
today i prototyped a similar add-on for owb, which allows to use @Autowired in cdi-beans to inject spring-beans based on the (field-)name or type. compared to the cdi-spring bridge i described here, it allows a simpler implementation which delegates to a started spring-container (instead of bootstrapping it). the major downside is that it isn't a portable cdi-extension (per definition) and therefore you can only use it with owb. furthermore, there is no validation of those injection-points during the startup you (might) know from cdi and injection of cdi-beans into spring-beans isn't supported as well.