Change from Managed to Structural Navigation in SharePoint 2013 publishing programmatically

I developped a WebTemplate based on a Publishing site definition. The publishing features activated Managed Navigation by default. And I was unable to find how to change it programmatically. Then I used SharePoint Manager 2013 and found in the web Properties following key: SPFeatureProperty

And this was the Value:

<?xml version="1.0" encoding="utf-16" standalone="yes"?>

<WebNavigationSettings Version="1.1">

  <SiteMapProviderSettings>

    <SwitchableSiteMapProviderSettings Name="CurrentNavigationSwitchableProvider" UseParentSiteMap="True" />

    <TaxonomySiteMapProviderSettings Name="CurrentNavigationTaxonomyProvider" UseParentSiteMap="True" />

    <SwitchableSiteMapProviderSettings Name="GlobalNavigationSwitchableProvider" UseParentSiteMap="True" />

    <TaxonomySiteMapProviderSettings Name="GlobalNavigationTaxonomyProvider" UseParentSiteMap="True" />

  </SiteMapProviderSettings>

<NewPageSettings AddNewPagesToNavigation="True" CreateFriendlyUrlsForNewPages="True"/>

</WebNavigationSettings>

I Compared it tot he value of a second web I configured through the SiteSetting interface:

<?xml version="1.0" encoding="utf-16" standalone="yes"?>

<WebNavigationSettings Version="1.1">

  <SiteMapProviderSettings>

    <SwitchableSiteMapProviderSettings Name="CurrentNavigationSwitchableProvider" TargetProviderName="CurrentNavigation" />

    <TaxonomySiteMapProviderSettings Name="CurrentNavigationTaxonomyProvider" Disabled="True" />

    <SwitchableSiteMapProviderSettings Name="GlobalNavigationSwitchableProvider" UseParentSiteMap="True" />

    <TaxonomySiteMapProviderSettings Name="GlobalNavigationTaxonomyProvider" UseParentSiteMap="True" />

  </SiteMapProviderSettings>

  <NewPageSettings AddNewPagesToNavigation="True" CreateFriendlyUrlsForNewPages="True"/>

</WebNavigationSettings>

So I started looking for the WebNavigationSettings Class and I found this Post: Working with publishing navigation in SharePoint 2013

Here ist the code like it should be in a feature receiver:

SPWeb web = (SPWeb)properties.Feature.Parent;

myNavigationSettings.CurrentNavigation.Source = StandardNavigationSource.PortalProvider;

myNavigationSettings.Update();

StandardNavigationSource is an enumeration and looks like this:

public enum StandardNavigationSource

    {

        Unknown = 0,

        PortalProvider = 1,

        TaxonomyProvider = 2,

        InheritFromParentWeb = 3,

    }