How to make the Apache reverse proxy server to support the long-polling connection?

Question

We have an Apache comet servlet on the Tomcat 8 server for the long-polling connection as below.

public class Connect extends HttpServlet implements CometProcessor {
    public void event(CometEvent event) throws IOException, ServletException {
        HttpServletRequest request = event.getHttpServletRequest();
        HttpServletResponse response = event.getHttpServletResponse();
        if (event.getEventType() == CometEvent.EventType.BEGIN) {
            event.setTimeout(300000);
            ...
        } else if (event.getEventType() == CometEvent.EventType.ERROR) {
            event.close();
        } else if (event.getEventType() == CometEvent.EventType.END) {
            event.close();
        }
    }
}

And the connector of the Tomcat8 server.xml as below

 <Connector port="8080" protocol="org.apache.coyote.http11.Http11NioProtocol"
               connectionTimeout="90000"
               redirectPort="8443" URIEncoding="UTF-8"/>

The comet connection will be timeout after 300 seconds. This is worked when client is trying to connect to the Tomcat directly.(http://IP:8080/Connect).

However, if we set up an Apache reverse proxy, the connection will always be timeout after 60 seconds. The Apache proxypass setting as below

ProxyTimeout 310
ProxyPass /Connect http://localhost:8080/Connect connectiontimeout=60 timeout=310 keepalive=On ttl=350
ProxyPassReverse /Connect http://localhost:8080/Connect

How can we make the long-polling connection works on the reverse proxy?

Thanks