Multisite installation in subfolder on IIS 7 – Network Admin 404 error

I’ve done a clean install of Multisite on an IIS 7 server. I put my WordPress install in its own sub-directory and adjusted my permalinks and index.php (now in the root directory) prior to running the Multipress setup. I’ve inserted all the setup code into the correct location of my wp-config.php and my web.config files.

The setup seems to be successful minus one thing, when I click on Network Admin from the dashboard I’m directed to a 404 Not Found page that is displayed in the Twenty-Thirteen fashion. The site is doing what I want it to by directing me to: mysite.com/wp-admin/network/, but I think I’m missing something in my web.config file because I can access the network admin page if I go to: mysite.com/wp_directory/wp-admin/network/.
Here’s my web.config setup:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <rewrite>
            <rules>
                <rule name="WordPress Rule 1" stopProcessing="true">
                    <match url="^index\.php$" ignoreCase="false" />
                    <action type="None" />
                </rule>
                <rule name="WordPress Rule 2" stopProcessing="true">
                    <match url="^([_0-9a-zA-Z-]+/)?wp-admin$" ignoreCase="false" />
                    <action type="Redirect" url="{R:1}wp-admin/" redirectType="Permanent" />
                </rule>
                <rule name="WordPress Rule 3" stopProcessing="true">
                    <match url="^" ignoreCase="false" />
                    <conditions logicalGrouping="MatchAny">
                        <add input="{REQUEST_FILENAME}" matchType="IsFile" ignoreCase="false" />
                        <add input="{REQUEST_FILENAME}" matchType="IsDirectory" ignoreCase="false" />
                    </conditions>
                    <action type="None" />
                </rule>
                <rule name="WordPress Rule 4" stopProcessing="true">
                    <match url="^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*)" ignoreCase="false" />
                    <action type="Rewrite" url="wp_directory/{R:1}" />
                </rule>
                <rule name="WordPress Rule 5" stopProcessing="true">
                    <match url="^([_0-9a-zA-Z-]+/)?([_0-9a-zA-Z-]+/)?(.*\.php)$" ignoreCase="false" />
                    <action type="Rewrite" url="wp_directory/{R:2}" />
                </rule>
                <rule name="WordPress Rule 6" stopProcessing="true">
                    <match url="." ignoreCase="false" />
                    <action type="Rewrite" url="index.php" />
                </rule>
            </rules>
        </rewrite>
    </system.webServer>
</configuration>

Any help would be greatly appreciated.