To copy a MailChimp campaign into Mandrill template you have to:
- Log in MailChimp and go in 'Campaigns'
- Click on 'My templates'
- Go on the template you want to copy on Mandril and select 'edit code'
- Copy the code and paste it in http://beaker.mailchimp.com/inline-css
- Convert the code and copy
- Go on a new Mandrill template and paste the code ^^