That is correct. The Beak VSM command is going to remove the SnapMirror Schedule. This is as per design.
From the description of the command:
'Terminates a VSM relationship – Quiesces the target volume, breaks the relationship and removes the schedule from the destination which releases the relationship from the source volume.'
As per your requiremetn, you will need to:
1. Clone the command 'Break VSM'
2. Remove the following lines of code from the command:
Get-WFALogger -Info -message $("Remove VSM schedule")
Remove-NaSnapMirrorSchedule -Destination ($snapmirror.Destination)
# connect to controller
Connect-WfaController -Array $SourceArray -VFiler $SourceVFilerName
Get-WFALogger -Info -message $("Release VSM relationship")
Invoke-NaSnapmirrorRelease -Destination ($snapmirror.Destination) -Source ($snapmirror.Source) -Confirm:$false
This will prevent your snapmirror schedule from getting deleted from your destination volume.
Also, this will prevent the snapmirror relationship details from being deleted from your source volume. This is to ensure your resync goes through successfully.