title: VSTO Signed, but still get confirm prompt at install
body: <p>I develop a VSTO addon for Outlook. I sign the addon with a certificate purchased with Verisign Inc. The cert is valid and authorized by a trusted root authority. But when my customers install the addon they are still prompted with "Do you want to install this addon from this publisher?" question.</p>
  
  <p>From what I understand Verisign cert is enough to make this go away, am I right?
  Is this prompt a mandatory in VSTO addon installation?</p>
  
  <p>Thanks</p>