Root cause description: Incompatible syntax changes for Apache 2.4
Solution description: Move default proxy_http config to ProxyPass syntax that is understood by both Apache 2.2 and 2.4

31700, 31701, 31702:
Root cause description: Default value of com.openexchange.usm.eas.ping.max_heartbeat is the same as grizzly timeout, leads to HTTP errors
Solution description: Increase default timeout in Apache's proxy_http.conf to 1900

Root cause description: Apache < 2.4 can't distinguish between BalancerMembers containing the same host but different timeouts for different Balancing Proxies
Solution description: Document workaround for Apache < 2.4 and set up combined balancing proxy for usm and eas

New configuration is outlined at http://oxpedia.org/wiki/index.php?title=AppSuite:Grizzly#Apache_configurat ion and distributed as part of the documentation examples within the open-xchange-core package