Good, you figure it out. There is no hope to expect slickedit automatically upload you changes into remote when changes are made to local mapped files. but when you open files remotely, you mapped directory will also keep a local copy. you can add this local copy into your project.
slickedit even can do remote building, so if you needed, please try it too.
This is how it works. If slickedit developers are watching this forums, I think it's decent to add remote files into project as well as local files. The great part of slickedit is to adopt to complicated environment, which normally doing programming on remote side.