Float MAC address in Heartbeat format

It's about a month I'm working about "High Availability" on Elastix based on DRBD and Heartbeat.

As you maybe be familiar with it, there is a file in Heartbeat called "haresources" that used for assigning primary server, replicated partition, starting services and finally creating a Float/Virtual IP address.

In haresources virtual IP address define with a format like "IPaddr::192.168.116.10/24/eth0/192.168.116.255".

As this virtual IP address created it will be assigned with a MAC address exactly the same as real interface.

Due to some problems on Voice Gateways, I think it's better to change the MAC address of virtual interface; but this changing should be placed on haresources and its format.

What should I do?!!

Thanks