<p>My rails app is in a svn repository, but several of the plugins are installed through git and later added to the svn repo.  How can I update these plugins?  I can't seem to get script/plugin update to do anything.  I'd really like to update activemerchant to get rid of the Inflector warnings.</p>

You should just be able to navigate to the plugin's directory and hit:
```
git pull
```
. I'm pretty sure that
```
script/install plugin
```
just checks the code out from the git repo.