Installing additional files with plug-ion

I am creating a plug-in which has some additional files, for example .js and .xap files for installation on the server – is it possible for me to create a zip package that contains the plug-in, and also the additional files?

I want to make it really easy for wordpress users to use the plug-in just by uploading it, I don’t want them to have to ftp or copy files around subfolders, which would be hard for any non-technical users.

If the above is not possible, I guess I’d like to know if it is possible that within the installation process, I can make my plug-in somehow download these files from my public server onto an appropriate directory?

regards
ewart.