I went to the address of zope manage:
localhost:8000/manage
Entered my plone_site named 'foo', than clicked on the portal_types link.
Went through the content type named 'MyContentType', and there clicked on the tab Permissions.
Changed some permissions to assign than to some roles, and so on...
Now, I went to the portal_setup to try to export this changes, but didn't find an option to export that.
I only found Role/Permissions, which is responsible for export changes on the 'main' tab Security, under the root of the plone_site.
So, how can I export my configuration on the permissions of specified content type under the portal_type tool?