Http-Invoker is not available in EAP6.x
However as an alternate approach you can expose your EJBs as web-services. The WebServices endpoints are accessible over http so you can then perform whatever operations you wanted to perform on the server side over http.
General, updating or change modules in EAP is not supported.
I suppose you have a subscription and use the Red Hat support portal. This support is based and provided on the EAP bits which are tested in exact this packaging. So change modules might affect the complete server. So if this is the case we ask for reproducing any issue with the original EAP version.