Why doesn't Ghost detect my offsite drive when it is reattached and then copy recovery point?

The manual says that when I plug my offsite drive back in it will be detected and recovery points will automatically be copied to it.  That does not happen.  I plug in my USB offsite drive, W7 recognizes it, but newer recovery points it is missing are not automatically copied.  I have to run a backup and wait for completion of the backup and the popup asking if I want to make an offsite copy.  

 

Is there a setting I am overlooking, or does Ghost 15 not automatically update an offsite copy when the drive is reattached?