Manually seeding an RDM VMDK

We are using ESX host based replication for our virtual machines. To expedite the backup process we copied their VMDKs to physical media so we could manually seed them at the backup site. We have a couple of VMs with RDM drives (in virtual mode) and have not been able to seed them the same way. We created the seed data by using WinSCP to connect to ESX and copied the contents of the each VM's folder (.vmdk, .vmx, etc) to an external drive.

Are there special steps required to do a manual seed of an RDM VMDK?