Changing html head tag in email campaign content

Changing html head tag in email campaign content

Does anyone know how to change the html head tag in the campaign?

Specifically I need to tailor the html head tag to the following to deal with Outlook compatibility:

<!DOCTYPE html>

<html xmlns=" http://www.w3.org/1999/xhtml"

xmlns:v="urn:schemas-microsoft-com:vml"

xmlns:o="urn:schemas-microsoft-com:office:office">

<head>

<!--[if gte mso 9]><xml>

<o:OfficeDocumentSettings>

<o:AllowPNG/>

<o:PixelsPerInch>96</o:PixelsPerInch>

</o:OfficeDocumentSettings>

</xml><![endif]-->

<title>XXX</title>

</head>