2.1.2 is fairly old... you should probably try a recent build.
And about the statement on "HornetQ isn't built for the WAN"...
That's a statement typical of sales people or Consultant people bringing "definitions" without the proper scientific or technical evaluation. That's definitely not the case and we have plenty of large deploymen cases using HornetQ as a central repository. I don't think anyone from either our support or our engineer would ever make such statement.
Anyone, back to the technical issue: you should try the latest bits as there are many, many fixes beyond 2.1.2... (Including failover and reconnection).
Just a statement to debunk the "built for the wan statement".. just look at the SpecJMS Horizontal submissions... the load is way beyond what you're experiencing now.