How to set HTTP-BIND timeout

I'm using ejabberd with the JSJaC 1.3.2 javascript library. On my Windows machine, after 1 minute, the HTTPRequest appears to reset itself - the status goes to 0 and the readystate goes to 4. USUALLY, JSJaC recovers, occasionally it doesn't an the chat session hangs. On my Mac, the connection does not reset itself and after 5 minutes, ejabberd sends back an empty reply, JSJaC sends another post and all is well. (So much for the background.)

How can I change the HTTP-BIND timeout on ejabberd so that it sends an empty reply every minute (or a little less than a minute) rather than every 5 minutes?

Thanks.

- Jasen.