WMIC ExportVirtualSystemEx Hyper-V?

Question

Hyper-V

Good day!
There is a powershell code:

$vmms = Get-WmiObject MSVM_VirtualSystemManagementService -Namespace "root\virtualization"
$a = 'Msvm_ComputerSystem.CreationClassName="Msvm_ComputerSystem",Name="3A9C5ECB-B5DF-4983-B8BA-4BF5765476FA"'
$vmms.ExportVirtualSystemEx($a, "d:\export\", "")

You need to write a wmic request.
This code doesn't work:

set a=Msvm_ComputerSystem.CreationClassName="Msvm_ComputerSystem",Name="3A9C5ECB-B5DF-4983-B8BA-4BF5765476FA"
wmic /namespace:\\root\virtualization path "Msvm_VirtualSystemManagementService" call ExportVirtualSystemEx %a%,"d:\export\",""

Mistake:

Invalid named parameter list.
Hint: <named param list> ::= <named param> | <named param> <named param list> where <named param> ::= <param name>=<param value>

If you remove or swap single and double quotes, "Description = Invalid method Parameter(s)" or "Invalid format" errors.

PS: The question is to make changes to the batch code in order for it to work, so please answer to the point.