Purpose
Speed Download is designed to work with all popular Mac OS X browsers. It is designed to become the download hub no mattter what browser you use.
The Apple Safari browser however, permits us to add extra functionality with Speed Download that results in an even greater downloading experience.
Resume Safari downloaded files with Speed Download! If you have downloaded a file with Safari partially, you can resume its download reliably with Speed Download. Simply drag and drop the Safari .download file onto the Speed Download icon in the dock, or into the 'My Downloads' section, and watch your file complete 100%.
Turn Speed Download 4 ON and OFF in real time with Safari: this specific feature set allows even more seamless integration with the Safari browser. Via the Safari contextual menu, you can easily disable/bypass Speed Download for certain sites, or completely disable Speed Download plug-in in the case of problematic servers. No need to restart Safari for changes to take effect!
If you right-click (control-click) anywhere in Safari, you will always see the Speed Download submenu from where you can choose to 'Disable Speed Download' (if you are experiencing some difficulty downloading from a particular site), or 'Download with Speed Download' (sends the file to be downloaded by Speed Download).
Furthermore, if you know for a fact that there is a sites that is not compatible with Speed Download (for whatever reason), you can instruct Speed Download to always let Safari do the downloading when it comes to that site.
This is all set in the Safari Integration section of the Speed Download preferences:

- you can enter full domains or subdomains. When you are downloading from a domain that is listed here; Safari will always do the downloading.
- from here you can also choose to completely disable the browser plugin in Safari.
The cool thing is that all changes take effect right away! No need to quit and restart Safari.
Notes:
If Safari is downloading a file; you can choose to stop it before it is complete and then drag that incomplete .download file onto Speed Download so that Speed Download can resume it. That way you can be assured that you'd be able to resume it fast should your internet connection drop (or something else go wrong).
The reason that we implemented this feature is because some sites use special scripting that doesn't always provide the necessary info to the browser in order to pass along to Speed Download and hence, Speed Download doesn't pick up the file. This is not a bug or shortcoming of Speed Download. Rather, most of the time it's site specific issues that don't adhere to standards that cause this.