How to scan system for new paths after adding additional FA ports

Issue

Description of problem:

We are adding 4 new paths to each multipath device.  Currently each mpath device has 4 paths so when we are done we expect to see 8.

Looking through the Online Storage Reconfiguration Guide for Red Hat Enterprise Linux 5 there isn't a clear method for how we might achieve this result.  The goal is to be able to perform this on a live system but only if we can do so w/out risk of data loss/corruption.

Please provide recommendation on how to accomplish this.  We need a recommendation by COB today, Sept 7th and this is why I am setting the severity to Urgent.