I may have found a workaround, that also deal with deployement / undeployement : http://www.jboss.org/mod_cluster
mod_cluster boasts the following advantages over other httpd-based load balancers:
Dynamic configuration of httpd workers
Traditional httpd-based load balancers require explicit configuration of the workers available to a proxy. In mod_cluster, the bulk of the proxy's configuration resides on the application servers. The set of proxies to which an application server will communicate is determined either by a static list or using dynamic discovery via the advertise mechanism. The application server relays lifecycle events (e.g. server startup/shutdown) to the proxies allowing them to effectively auto-configure themselves. Notably, the graceful shutdown of a server will not result in a failover response by a proxy, as is the case with traditional httpd-based load balancers.
Server-side load balance factor calculation
In contrast with traditional httpd-based load balancers, mod_cluster uses load balance factors calculated and provided by the application servers, rather than computing these in the proxy. Consequently, mod_cluster offers a more robust and accurate set of load metrics than is available from the proxy. (see Load Metrics for more)
Fine grained web-app lifecycle control
Traditional httpd-based load balancers do not handle web application undeployments particularly well. From the proxy's perspective requests to an undeployed web application are indistinguishable from a request for an non-existent resource, and will result in 404 errors. In mod_cluster, each server forwards any web application context lifecycle events (e.g. web-app deploy/undeploy) to the proxy informing it to start/stop routing requests for a given context to that server.
AJP is optional
Unlike mod_jk, mod_cluster does not require AJP. httpd connections to application server nodes can use HTTP, HTTPS, or AJP.
The original concepts are described in a wiki.
I hope that will help.