Datacolor User to User Support Group.

Can someone tell me the workflow for building a profile with the 
Extended Gray?
Do you first read and build a color profile from say, the "Fast Target" 
then read the Extended Gray target?
It seems when I attempt to build a profile with the Gary it wipes out 
the color profile and then tells me "...you can't build a profile from 
just the gray target...".
So, I'm lost...what is the workflow?
Thanks in advance...
Jack