title: How can I call New-AzureStorageContext using -SasToken instead of -StorageAccountKey
body: <p>Using Azure Powershell v1.3, I'm trying to create a new storage context using an existing Shared Access Signature token which references an existing policy. When I call <code>New-AzureStorageContext</code> with <code>-SasToken</code> and <code>-StorageAccountName</code> I get an error:</p>
  
  <pre><code>PS C:\&gt; $ctx = New-AzureStorageContext -SasToken '?sr=c&amp;sv=2015-02-21&amp;si=ReadOnly&amp;sig=&lt;signature omitted&gt;=&amp;api-version=2015-04-05' -StorageAccountName 'mystorageaccount'
  
  New-AzureStorageContext : An item with the same key has already been added.
  At line:1 char:8
  </code></pre>
  
  <p>I feel like I'm getting the format of the SAS token wrong, or am missing a step or parameter, but there are no examples on what it should look like, and this is the only SAS form I've been able to query from Azure. </p>
  
  <p>Note I don't want to use <code>New-AzureStorageAccountSASToken</code> (which all examples use) because I already have a token, and just want to use it for read-only purposes, so I don't need to use the storage account keys. Creating a new one would require permissions I don't want this client to have.</p>
  
  <p>What is the missing syntax / step?</p>