Backing up CCRLCR and E2K7
One of the advantages of using CCR and\or LCR is the ability to offload the backups to the passive copy of your data. It means that you don't have to take the same performance hit (particularly important if you are running a 24-hour operation) and it also means that your IS maintenance doesn't get interrupted.
One thing to keep in mind though is that streaming backups are only supported from the active storage groups. If you want to backup your passive copy the only solution is to run a VSS backup.
With a VSS backup the replication service works with the store on the active node (not the passive) to ensure that database headers are updated appropriately when a VSS backup is run, to avoid database divergence. This means that the information store is kept up to date with which transaction logs can safely be truncated. The information as to how this will work in practise seems a bit patchy as this will be handled by 3rd party software and each vendor will presumably approach this a bit differently...