Checking over a web.config for a current v7 site I've been working on, the umbracoConfiguration/settings section is of type Umbraco.Core.Configuration.UmbracoSettings.UmbracoSettingsSection
.
Another thing you're doing wrong is using as IUmbracoSettingsSection
. As means if the cast fails you return a null object, rather than an exception telling you the cast failed - it fails silently. It is better to do:
var umbracoSettings = (IUmbracoSettingsSection)ConfigurationManager.GetSection("umbracoConfiguration/settings");
As mentioned, I think your base type is wrong, and you should actually use:
var umbracoSettings = (Umbraco.Core.Configuration.UmbracoSettings.UmbracoSettingsSection)ConfigurationManager.GetSection("umbracoConfiguration/settings");
This should cast the section into the correct type for you.