title: unable to get snapshotAvailableSpace of a softlayer endurance storage
body: <p>I am looking for <em>"space left"</em> from the <em>"total space reserved for snapshots"</em> on a endurance storage volume. I tried the following, but snapshotSpaceAvailable property did not show up.</p>
  
  <p><strong>REST CALL:</strong></p>
  
  <pre><code>https://api.softlayer.com/rest/v3/SoftLayer_Network_Storage/VOULME-ID?objectMask=id;notes;nasType;capacityGb;snapshotCapacityGb;snapshotSpaceAvailable;snapshotCount
  </code></pre>
  
  <p><strong>O/P:</strong></p>
  
  <pre><code>&lt;root&gt;&lt;capacityGb&gt;100&lt;/capacityGb&gt;&lt;id&gt;VOLUME-ID&lt;/id&gt;&lt;nasType&gt;ISCSI&lt;/nasType&gt;&lt;notes&gt;NotesOnStorageVolume&lt;/notes&gt;&lt;snapshotCount&gt;30&lt;/snapshotCount&gt;&lt;snapshotCapacityGb&gt;5&lt;/snapshotCapacityGb&gt;&lt;/root&gt;
  </code></pre>
  
  <p>Am I missing something here? Please help me get the value for  snapshotSpaceAvailable for a storage volume. thank you!</p>