URL Rewrite 404 error – WP Network on IIS 7.5

I’m stuck.

I’m having 404 trouble when setting up a simple(?)WP Network – after newly installed WP 3.8.1 on a IIS 7.5 server. Guessing that my problem is in the URL re-write rules that WP supplied me with. I don’t know how to set them straight.

My main site still works fine after I set up the network, but sub sites loads content but cant find CSS-files (404). Also get 404 trying to reach wp-admin for sub-sites. AS mentioned, I used the web.config that was supplied by the network-installation, so I haven’t meddled with it.

I’m trying to use directories, not sub-domains.
* inside.companyname.com (main-site)
* inside.companyname.com/sales (sales wanted a seperate site)
* inside.companyname.com/testarea (seperate testsite for theme-modding)

https://inside.companyname.com/wp-admin (works!)
https://inside.companyname.com/wp-admin/network (works!)
https://inside.companyname.com/sales/wp-admin (gives 404!)

This is the web-config that I used:

<?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="{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="{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>

wp-config

/* Multisite */
define( 'WP_ALLOW_MULTISITE', true );
define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', false);
define('DOMAIN_CURRENT_SITE', 'inside.companyname.com');
define('PATH_CURRENT_SITE', '/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);

Appreciate the help!