Hidden field in subscription form

Hi all!

I am new at responsys and I face difficulties when trying to configure a custom unsubscribe link in message.

I followed the below steps:

• I created a form (in order to use it as a landing page upon unsubscription)
  • I inserted just an html file and no other configuration
  • In the html file , i used the $EMAIL_PERMISSION_STATUS_$ field as a hidden field by giving an 'O' value
• I created a campaign where:
  • At campaign setup I chose "No footer"
  • I used an unsubscribe link inside the message as follows: ${form('MyForm',{},'unsubCampCreditString='+unsubCampCreditString)}

Based on the other topliners articles, the above link should unsubscribe contact.