Apologies for the delay in response.
Here are the PowerShell commands for your reference.
PS C:\> $vpnSite = Get-AzVpnSite -ResourceGroupName "test-VWAN-RG" -Name "test-vpn-site"
PS C:\> $vpnSitesForConfig = New-Object Microsoft.Azure.Commands.Network.Models.PSVpnSite[] 1
PS C:\> $vpnSitesForConfig[0] = $vpnSite
PS C:\> $virtualWan= Get-AzVirtualwan -ResourceGroupName "test-VWAN-RG" -Name "test-vwan"
PS C:\> Set-AzCurrentStorageAccount -ResourceGroupName "RG01" -AccountName "mystorageaccount"
PS C:\> New-AzureStorageContainerSASToken -Name "Test" -Permission rwdl
Note: Add a blank test.txt file in the container vpnsiteconfig and then click on test.txt file copy the URL and append the generated SAS URL at the end of the blob URL, use the complete URL in the below command
PS C:\> Get-AzVirtualWanVpnConfiguration -VirtualWan $virtualWan -StorageSasUrl "https://config3423423.blob.core.windows.net/vpnsiteconfig/test.txt?sv=2019-02-02&sr=c&sig=DUyllNNbnF28b2gocb%2Bhjqt8YHorKckHdlLQ%3D&se=2020-08-17T17%3A21%3A50Z&sp=rwdl" -VpnSite $vpnSitesForConfig
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