Editing of remote files using FTP is possible using an Eclipse plug in called Remote Systems Explorer (RSE), which is part of the Eclipse Target Mangement Project.

To install Target Mangement, go to Install New Software...  under the Help menu.  The go and add the location:

http://download.eclipse.org/dsdp/tm/updates/3.0

and then check the box next to "TM and RSE 3.1.1" (or a newer version if one is available) and click Next to complete the install.