Keeping configuration transforms after applying EPiServer 7 Patch

When installing the patch 1 for EPiServer CMS 7 the installation instructions stated that you needed to turn of the msbuild build tasks that created the configuration files from different xml fragments using xml transform.
The patch also noted that you needed to manually replace the assembly redirect assembly versions directly in the web.config file.

Since I have grown quite fond of using the xml fragments to apply configuration changes for our entire development team I found a way to apply the patch changes by a simple xml transform.
Just edit the [Configuration]/Common/Web.Common.config and add the redirects that you need to fix.

<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform" xmlns:asm="urn:schemas-microsoft-com:asm.v1">
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly xdt:Transform="Replace" xdt:Locator="Condition(asm:assemblyIdentity/@name='EPiServer.Framework')">
        <assemblyIdentity name="EPiServer.Framework" publicKeyToken="8fe83dea738b45b7" culture="neutral" />
        <bindingRedirect oldVersion="1.0.0.0-7.0.859.4" newVersion="7.0.859.4" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

The key here is that we replace the original assembly redirect with the new binding (with the new version number) and use a Locator attribute to find the correct node in the original web.config file to replace.

The tricky part in this case is that the assemblyBinding changes the default namespace. To get a correct xpath we need to use this namespace to locate the child node. To use a namespace in an xpath expression we first need to register it with a prefix (here using asm) in the root node (or somewhere in scope). We can then build a correct xpath expression (asm:assemblyIdentity/@name) to locate the node.

I will follow up with a final post stating all adjustments needed to get this to work.

Update/follow up
I completed the adjustments for both the Framework and CMS packages and collected the needed transforms in the following file.
https://dl.dropbox.com/u/10119568/EPiServerCms7Patch1/web.common.config
The installation instructions also stated that other assemblies could be present (in my case there wasn't) but if that's so in your case, just add those transformations to the list.)

Note: I needed to remove the old dll:s from the [Libraries] folder in the Alloy template or my VisualStudio didn't get the hint path correctly.