ASR Use powershell to re-protect. Failback from Azure to VMware

I have an ASR appliance in VMware replicating a Vm to Azure. I want to automate failover and failback. I was able to do the test failover and cleanup with powershell.

Start-AzRecoveryServicesAsrTestFailoverJob -ReplicationProtectedItem $ReplicationProtectedItem -Direction PrimaryToRecovery -AzureVMNetworkId $TFONetwork

and

Start-AzRecoveryServicesAsrTestFailoverCleanupJob -ReplicationProtectedItem $ReplicationProtectedItem -Comment "Testing Completed"

This worked! Next, an Unplanned failover

Start-AzRecoveryServicesAsrUnplannedFailoverJob -ReplicationProtectedItem $ReplicationProtectedItem -Direction PrimaryToRecovery -Confirm:$false and then commit

Start-AzRecoveryServicesAsrCommitFailoverJob -ReplicationProtectedItem $ReplicationProtectedItem

that worked! I then logged into the new Azure VM, and created a text file on the desktop. Now I want to failback the Azure VM to VMware. To re-protect I have been trying Update-AzRecoveryServicesAsrProtectionDirection with no luck.

Update-AzRecoveryServicesAsrProtectionDirection -ReplicationProtectedItem $ReplicationProtectedItem -Direction RecoveryToPrimary -Confirm:$false

This fails with "Object reference not set to an instance of an object." I don't know the difference between using "-Direction RecoveryToPrimary" and "-AzureToVMware". They seem like the same thing.

In the GUI if I start re-protect, I see it asks for 'vCenter Server/vSphere Host' (already filled in with my vCenter), 'Datastore' (already got my vCenter datastore), 'ASR Replication Appliance' (already there) and 'Cache storage account',

If I try Update-AzRecoveryServicesAsrProtectionDirection -AzureToVMware it then asks me to fill in the parameters, datastore ..i give value shown in GUI ... 'L1DS-SRV02' processServer .. I assume this is ASR app in my vCenter .. I give value shown in GUI ProtectionContainerMapping : don't know this one

But it gives me errors like :
Cannot bind parameter 'DataStore'. Cannot convert the "L1DS-SRV02" value of type "System.String" to type "Microsoft.Azure.Commands.RecoveryServices.SiteRecovery.ASRDataStore".

-- Can anybody help me formulate the powershell commands to do a re-protect and failback to VMware and then get replication back to where it was in the beginning, VMware to Azure? Also to get the values needed for Update-AzRecoveryServicesAsrProtectionDirection in the right format . thanks in advance.