I - This forum is for Development only. (Users are always welcome to join the dev-forums though. as long as it is a development topic). (Development != Developer)
this question should be moved to user's forum. (I will ask someone with privileges later).
II - You have to configure the ConnectionFactories to have a backup node associated. You should read the manual.
III - We are improving failover ATM: The dev thread is here: http://community.jboss.org/thread/152610?tstart=0