I am hoping you have the -C module which would have shipped with the NET+OS development environment. You should be able to create a working .bin file from within ESP. Whatever you do, you probably want to include ftp as a component of the application. This would allow you to load newer applications.
From within ESP new->net+os project
When yo get to a list on services to include, make sure that http or web and ftp are checked. Also include anything else you need.
Under the project in ESP there are Debug and Release directories depending on if you are building in Debug or Release modes. Whichever there should be an image.bin file created in the directory that corresponds to the mode you built in. You should be able to ftp that image into the device.