I believe you need to be on the same wifi network with your mobile device/laptop to be able to send prints to the 6515. Unless you are using some other tool I am not aware of, what you are describing won't work with the Wifi adapter.
Thanks, CathyO-Xerox Community Manager
Be sure to click Kudos for those who have helped you. Select Accept as Solution for posts that have helped to solve your issue(s)!