i need a little help

i'm just a junior developer and right now i have to work with jackrabbit..
i have a little problem with configuration of indexing, and i read something about it on wiki and read some comments, but i can't find a solution.
i've configured a repository with my own types of node with namespace "th", and when i try to index some nodes my indexing-configuration are ignored! i don't know why (i try to play with default nodes and it realy work, but with my custom nodes no).

this is my indexing-configuration:

<?xml version="1.0"?>
<!DOCTYPE configuration SYSTEM "
<configuration xmlns:jcr="
http://www.jcp.org/jcr/nt/1.0" >

 <index-rule nodeType="th:hierarchyNode" boost="2.0">
  <index-rule nodeType="th:resource" boost="4.0">

  <index-rule nodeType="th:metadata" boost="2.0">

  <index-rule nodeType="th:fileDocument" boost="2.0">

  <index-rule nodeType="th:plainDocument" boost="2.0">

as it can be seen the plainDocument is not configured to be indexed , but when i run a search i can find it and i even looked at the index on filesystem and i found mark of this node beenig indexed

i hope you can help me.
lots of 10x,
ana r.