I use WinSCP to maintain/update web files from a linux host. As a temporary directory I use "My Documents/webwork" In a version prior to 4.1.8 it appeared that the edited file was stored in the directory "My Documents/webwork/scpnnnnn" (where n is temporary random number). The edited file was stored imediately under the scp.... directory regardless of its directory tree location on the server. This allowed me to put an /images and /style directory within My Documents/webwork and with a relative reference to images and style sheets my external editor (Kompozer) was able to pick up these files so my display showed the web page as it would appear on the live site.
Was something changed in 4.1.8 since now the directory structure of the edited file appears under the scpnnnn directory and the relative references no longer work.
I agree this is not the most sophisticated approach but I'm not aware of any other local editor methods that allows me to access the server based pages and get some reasonable fidelity to the original look of the site.
If you or anyone has other suggestions I'd very much like to hear them. I'm not wedded to komposer, but it does provide both wysiwyg as well as raw source editing which is needed on .jsp pages.