I think you can´t. See the blog post at:
http://enblog.doit.im/post/25994485658/how-to-add-task-via-email
The last sentence reads: "Here, keep it in mind that emailed tasks will go directly to your own Inbox. That is to say, only in Inbox can you find the task from an email. "
http://enblog.doit.im/post/25994485658/how-to-add-task-via-email
The last sentence reads: "Here, keep it in mind that emailed tasks will go directly to your own Inbox. That is to say, only in Inbox can you find the task from an email. "