title: Clearing the value of a Multi-Select Picklist using API
body: <p>I have a very simple question - How do I use the PHP Soap API to clear the value of a Multi-Select picklist in Salesforce? I can update other fields to my heart's content, but if I try and update that field with an empty string, it does nothing.</p>
  
  <p>I know I'm missing something simple about this, can someone point me int he right direction?</p>