The pages.Insert(0, DataFactory.Instance.GetPage(pageLink)); will create a infnite loop.

Have you set ShowRootPage=true?

I hadn't found that one. But now when I tried it I didn't get the result I wanted. I wanted the startpage on the same "level" as its children but not the same as its grandchildren.

This structure should result in this code:

Structure:

Start
 - News
 - About
 - Examples
   -Test

Code:

<ul>
<li>Start</li>
<li>News</li>
<li>About</li>
<li>Examples</li>
<ul>
<li>test</li>
</ul>
</ul>

And the only way i found so to do what I tried to do. Why does the pages.Insert trigger that function again? :/

Take a look at MainMenu.ascx.cs in the PublicTemplates project (/Templates/Public/Units/Static/MainMenu.ascx.cs).

protected override void OnLoad(System.EventArgs e)
{
    base.OnLoad(e);

    Menu.PageLink = PageReference.StartPage;
    Menu.PageLoader.GetChildrenCallback = new HierarchicalPageLoader.GetChildrenMethod(LoadChildren);
    Menu.DataBind();
}

/// 
/// Creates the collection for the main menu, adding the startpage
/// 
private PageDataCollection LoadChildren(PageReference pageLink)
{
    PageDataCollection pages = DataFactory.Instance.GetChildren(pageLink);
    pages.Insert(0, DataFactory.Instance.GetPage(pageLink));
    return pages;
}

My code is based on that code, but the "pages.Insert() causes an infinite loop and I can't understand why.

Ops sorry, was a bit fast posting that :). What happens if you use all the code in MainMenu.ascx (just use that user control instead of your own), do you get the same error?

It works perfectly with the Menu-control that is in the MainMenu.ascx as default. No error.