VMware's document stated " You can't use Consolidated Backup to backup virtual machines in a cluster. These VM shares an SCSi controller and snapshot operations can't be performed on them."

I have a cluster with two ESX 3.5. All the VMs are on a iSCSI storage. Is that mean I can't backup all my VMs? if so, is there any other way to backup VM without buying third party software?

Thank you,