Hi,
I do think Safari should be added as a supported browser for exactly the reason you stated. I don't know if the PC-Windows version is equivalent to the Mac version, but I do find problems with many pages loading or operating incorrectly at Auctiva with the Windows version.
Danno
Edit: I have a tip you might want to try in Safari. Apparently, Safari can masquerade as another browser. To turn-on the feature, goto the Advanced icon in Preferences and click-on the "Show Develop menu in menu bar". With the Develop drop-down on toolbar (now added), select the User Agent and try "Firefox 2.00.12 -Windows (or - Mac)". I tried the Windows, and did get some progress on tests of things that formally failed (like the Description window on the one-page). The Aurigma uploader worked too. Note, this feature was reported as added to Safari 3.1.