action at IP takeover

Hi,
I want to use wackamole to build a high available firewall. To achive
this, I need to notify conntrackd (which I use to replicate the
netfilter statetables) when the server, it is running on, becomes
responsible for the virtual IP. How can I do this? Is there any way to
define a script, that is called at IP takeover?

Thanks for all your help!
Maik