I am also looking for an answer to this question and would appreciate any help offered.
You can not access items bound to the 'java:' namespace remotely.
You do not say which JBoss version you are using so the following may or may not work.
Have a look at the following page on configuring datasource: -
You need to use the '<use-java-context>' element and set it to false so the datasource will be bound to the global context instead.