To enable 1password in Safari 4 Beta:
- Quit Safari
- Locate 1Password in your /Applications folder
- Ctrl-click > Show Package Contents
- Contents > Resources > SupportedBrowsers.plist
- Root > Safari > MaxBundleVersion > Change value to 5528.16
- Start Safari
Works great for me.
I didn’t mention this in the main post, but the “1P” button doesn’t show up, but the keyboard shortcuts still do. Command-\ is your friend. (Thanks, Etay.)
There’s a new beta of 1Password that supports Safari 4 beta. Go to Preferences → Updates, make sure you have “Include Beta Versions” checked and update.