How can I get .pkpass files on my Mac to Passbook on the iPhone?

I've used Passbook sucessfully on my iPhone before (boarding passes). However, I just downloaded an .pkpass file from a web site to my Mac, and I can't get the pass to the iPhone.

If I double-click on the file, something called Pass Viewer asks if I want to send the ticket to my Passbook. I say yes, and it appears to work. If I double-click again, the view says that ticket is already in my Passbook, but it doesn't appear on the iPhone.

I'm logged into the iCloud on the Mac, and I have iCloud support enabled on the iPhone for Passbook. Why does the Mac believe the pass has been sent, but the iPhone can't see it?

-- ross