Hi, I am also a Media Temple customer and its knowledgebase has not been updated with this issue although it is very frequent from what I see.

Thank you very much.

I changed the nginx.conf file adding the lines you mentioned and then restarted.

It also helped me a lot finding the nginx restart command on the blog post you mentioned:
kill -HUP `ps -ef | grep nginx | grep master | awk {'print $2'}`