Responsive Email Templates Inserted Inside 600px Table

Responsive Email Templates Inserted Inside 600px Table

I am currently trying to import responsive email templates we have created in to campaigns. I am running in to an issue where the template gets set within a 600px table once I get past the import screen, and persists when sending a test email.

This is the specific code that campaigns seems to be inserting:
  1.   <body class="ze_body" style="font-family:Verdana,arial,Helvetica,sans-serif;font-size:13px;">
  2.    <center>
  3.    <table width="600" style="margin-top:20px;"  cellspacing="0" cellpadding="0" border="0">
How can we override this table so that we can use responsive email templates?