PLC 5 redundancy issue

I have a plc 5 system with 5/80e processors and have bcm redundancy modules, I have a wonderware system using ethernet to talk to the processors and would like to know what will happen when the primary becomes the secondary and wonderware polls the primary. I am under the understanding that plc5 redundant systems do not swap IP addresses, how can I make the plc's swap IP addresses.

We had a similar proble a few years ago, except we were using Citect instead of Wonderware. Rather than change the PLC's ip address we ended up getting Citect to swap PLC that it was talking to.
What we did was to set a bit in the PLC that would only be ON if that PLC was the one controlling the process. The n we wrote code in Citect that would disable that IOdevice and enable the other one if it ever found that it was "talking" to the standbv PLC.