As Alberto has shown, with FTP you need to set the path to the folder in the address book. For example, if the Scans folder is located under the Desktop, then the path would be /Desktop/Scans
As for using Image Capture, the 6015Ni would need an ICA driver to be used with this application. Apple does not appear to have an ICA driver for this printer so you would need to check if Xerox has one.
And for the Fax component to be present in Print and Scan, you would require a fax driver to be installed. Then if you selected to add the 6015Ni again, you should see an entry for the printer AND an entry with Fax. Selecting this and linking it to the Fax driver would then give you a new "Printer" that can be used for faxing from the Mac.