ASP读取XML的时候遇上空值，使用XPATH应该怎么办呢

ASP读取XML的时候遇上空值，使用XPATH应该怎么处理呢？
假设有个这样的XML

<bookstore>

  <storename>小寨店</storename>

  <storetel>029-8888 8888</storetel>

  <storeaddr>西安市长安中路100号</storeaddr>

  <bookclass>

    <classname>社科类</classname>

    <classadmin>李四</classadmin>

    <classlist>

      <bookname>XXX时代</bookname>

      <bookprice>CNY90.00</bookprice>

      <bookpress/>

    </classlist>

  </bookclass>

  <bookclass>

    <classname>小说类</classname>

    <classadmin>王五</classadmin>

    <classlist>

      <bookname>冰与火之歌1</bookname>

      <bookprice>CNY70.00</bookprice>

      <bookpress>HBO出版社</bookpress>

      <bookname>冰与火之歌2</bookname>

      <bookprice>CNY70.00</bookprice>

      <bookpress>HBO出版社</bookpress>

      <bookname>冰与火之歌3</bookname>

      <bookprice>CNY70.00</bookprice>

      <bookpress>HBO出版社</bookpress>

    </classlist>

  </bookclass>

    <classname>IT类</classname>

    <classadmin>张三</classadmin>

    <classlist>

      <bookname>C语言基础教程</bookname>

      <bookprice>CNY20.00</bookprice>

      <bookpress>高等教育出版社</bookpress>

      <bookname>Think in C++</bookname>

      <bookprice>CNY90.00</bookprice>

      <bookpress>清华大学出版社</bookpress>

      <bookname>Think in Java</bookname>

      <bookprice>CNY89.00</bookprice>

      <bookpress>清华大学出版社</bookpress>

    </classlist>

  </bookclass>

</bookstore>

在读取bookclass节点的时候，如果其子节点（或者是孙节点，反正是下面的节点）中有个值是像例子里面那样，空的，直接用<bookpress/>的，就不读取了，直接读取下一个。

我今天试着用selectNodes("classlist/bookpress[not(text())]")，不行，不知道是哪里的问题。求各位高人解答..
XML是没办法改的，这是个webservice传递过来的的结果。
------解决方案--------------------
selectNodes("/bookstore/bookclass[classlist/bookpress[.!='']]")
------解决方案--------------------

Set objXML= CreateObject("MSXML2.DOMDocument")

'===

set objStore= objXML.getElementsByTagName("bookstore")