How do I convince iTunes to play a podcast item I've manually replaced I'm subscribed to a podcast which recently had two episodes listed with links to files which were only a few bytes big. I have no idea what went wrong on their end, but my copy of iTunes downloaded these, and I could 'play' them.

Now the songs on the server have been updated, but I cannot convince iTunes to re-fetch the files. Removing the podcast is not an option as I have 4 years of history from that podcast saved locally and I don't want to lose it.

I'm a software developer myself, so I figured, I'll just use curl and manually get the updated files, copy them over the originals, restart iTunes, and all will be well. Not so. iTunes is still playing less then a second of the file before stopping again. However, I can hear the start of the actual podcast now, so it's playing the new file, and it has also updated the length of the file (as displayed in the podcast's list of items in iTunes itself) to something I assume is correct, much longer than the 0 seconds it was before.

The mp3 files themselves play fine in VLC. How can I get iTunes to normally recognize the new files?

(if it matters, I'm on Lion with all the latest updates. iTunes version 10.5.1. I'm not syncing with any other devices.)
Delete the corrupted episode
Opt/Alt-click on the triangle in front of the Podcast name
All available episodes will be displayed in addition to the ones you already downloaded, together with a button to download them individually