Hi,
I dont have idea about Unitrends.
If vMotion is not available, try OVF export method as suggested by VMware. In this case, you have to come up with some idea to transport the ovf files to DR site.
Else, you can allocate a lun from your DR site, mount it to existing environment and use VMware Converter and create clone VM's in the newly mounted DR lun. Once completed, unmount the DR lun and mount it in DR site and power-on the VM's.