How can I force MMS messages to retry? I used to have this problem with my Nexus One on T-Mobile, and now have it again on my Samsung Galaxy SII on Sprint. It seems like about every other MMS message I get will fail to download. It'll just sit in that "downloading" state forever. (Note: it is not actually a pattern of every other time.) I have the stock Android messaging app that comes with the phone.

I have found dozens of threads about this out there on various Android forums, but all of them seem to be pre-ICS and so I don't have the settings the solutions refer to. The solutions all seem to be really esoteric, too.

If I can make it stop getting "stuck" that's great, but I figure the easier question is as posted: once it gets in that stuck state, how can I force it to restart the download? That'd be enough to fix the issue for me.
Got to the bottom of this. If your data connection isn't on when someone sends you an MMS, the download has a tendency to hang. If you shut off the connection to save battery or have any app that does this (like Juice Defender), this will happen to you a lot. Go into the MMS app's settings and turn off the "auto retrieve" option for MMS and you should be right as rain.