[TYPO3] Sitemap: excluding subpages of a page

[Claudio Strizzolo]

Hi all,
I am trying to build a sitemap with the following requirements:

- display only the first two levels of the pages tree;
- do not display second level pages that are below a first level 
  page whose id is x (let's say: 100);

i.e. I have this tree:

10
   11
   12
20
   21
   22
100
   101
   102
110
   111

And I want just this sitemap to be displayed:

10
   11
   12
20
   21
   22
100
110
   111

I tried with the following code, but it does not work: all the pages
at second level are displayed. Look in particular at the "if" context in 
the second level settings.

tt_content.menu.20.2.wrap >
tt_content.menu.20.2.stdWrap.wrap = <div class ="sitemap">|</div>
tt_content.menu.20.2 {
  1 {
    noBlur=1
    expAll=1
    wrap = <ul>|</ul>
    NO {
      stdWrap.field=title
      allWrap >
      wrapItemAndSub = <li>|</li>
    }
  }
  2 = TMENU
  2 { 
    noBlur=1
    expAll=0
    wrap = <ul>|</ul>
    NO {
      stdWrap.field=title
      allWrap >
      wrapItemAndSub = <li>|</li>
    }
    if {
      value=100
      equals.field=pid
      negate=1
    }
  }
}

I know that I might use the excludeUidList argument to exclude the 
subpages under 100 (i.e. 101 and 102), but actually there are a lot of 
them, and they are often added/removed, so the situation is very dynamic.
Any hints?
Thanks in advance

Claudio