This can be achieved in two ways. First I would add "EXEC1001=BrokerConfig.exe, /r, INSTALLONLY" to your agent using Advance Edit. This line needs to be placed under [Policy Management Post Copy] section if you are using version 9 SP2. If using earlier version it needs to go under [Common Base Agent Post Copy]. Now you can either deploy out your agent again or you can create a script that will run the command "BrokerConfig.exe /r" and push to those agents that are already out there.