[Pound Mailing List] Change backends without downtime

Hello,

I'm using the latest version of pound with Ubuntu and the default pound.cfg
file. I have two backends on the same IP but different ports (8080/8081).
When I deploy a new version on backend 8081, I active it and deactivate
backend 8080. By doing this, the user that were on 8080 are still served by
8080 (which is actually disabled). Then I turn off 8080 backend tomcat, so
it will be DEAD. The users on 8080 will then see the downpage, but after a
refresh, they will be redirected to 8081.

How can I switch backends without displaying the downpage?
Thanks,
Silvan