Why won't the real player video download button pop up on videos I watch when...

...I'm on Safari browser? The real player video download button pops up when I'm on Internet Explorer, but not when I'm on my Safari browser. I have windows vista home basic. Any idea of why this may be happening and how I can correct the problem? Is real player downloader compatible with Safari? Is there some type of plugin I need or some setting I need to fix? I really want to download videos from the internet with Safari since its way faster than Internet Explorer.