UV Mapping - How to use multiples materials and images for one object

[micheus]

but for a more complex shape, the re-selecting process can be a hassle. A trick there, is to convert all your materials into selection groups before you UV, and then reapply the old materials using your selection groups

I did't get your point here. Once you have the uvma material in the Outline window you just use the select option for the material. Why would we have to add a second way to select the same thing?