New Post: importing custom fields (xml data)

This is the XML file I try to import without success!!! I thy to make this example for UPDATE the category association to my product. But it don't work!

Please try to save this following code in a xml file, import it and show that for this article there aren't any categories
I follow all the documentation funded in the forum... but nothing?!?
What it's wrong?
Can you help me
thanks
Fabio

<root version="1.0">
  <products>
    <en-US>
      <P>
        <NB_Store_ProductsInfo>
          <ProductID>100</ProductID>
          <PortalID>0</PortalID>
          <TaxCategoryID>-1</TaxCategoryID>
          <Featured>false</Featured>
          <Archived>false</Archived>
          <CreatedByUser>1</CreatedByUser>
          <CreatedDate>2013-02-05T17:24:15.78</CreatedDate>
          <IsDeleted>false</IsDeleted>
          <ProductRef>X10NDA610</ProductRef>
          <Lang>en-US</Lang>
          <Summary>10NDA610</Summary>
          <Description>DES</Description>
          <Manufacturer />
          <ProductName>X10NDA610</ProductName>
        </NB_Store_ProductsInfo>
        <C>
          <NB_Store_ProductCategoryInfo>
            <ProductID>100</ProductID>
            <CategoryID>8</CategoryID>
          </NB_Store_ProductCategoryInfo>
          <NB_Store_ProductCategoryInfo>
            <ProductID>100</ProductID>
            <CategoryID>19</CategoryID>
          </NB_Store_ProductCategoryInfo>
        </C>
      </P>
    </en-US>
  </products>
  <categories>
    <en-US>
      <NB_Store_CategoriesInfo>
        <CategoryID>18</CategoryID>
        <PortalID>0</PortalID>
        <Archived>false</Archived>
        <Hide>false</Hide>
        <CreatedByUser>1</CreatedByUser>
        <CreatedDate>2014-01-16T12:10:00.803</CreatedDate>
        <ParentCategoryID>0</ParentCategoryID>
        <ListOrder>30</ListOrder>
        <Lang>en-US</Lang>
        <CategoryName>By Technologies</CategoryName>
        <ParentName />
        <CategoryDesc />
        <Message />
        <ProductCount>0</ProductCount>
        <ProductTemplate />
        <ListItemTemplate />
        <ListAltItemTemplate />
        <ImageURL />
        <SEOPageTitle />
        <SEOName />
        <MetaDescription />
        <MetaKeywords />
      </NB_Store_CategoriesInfo>
      <NB_Store_CategoriesInfo>
        <CategoryID>19</CategoryID>
        <PortalID>0</PortalID>
        <Archived>false</Archived>
        <Hide>false</Hide>
        <CreatedByUser>1</CreatedByUser>
        <CreatedDate>2014-01-16T12:10:39.823</CreatedDate>
        <ParentCategoryID>18</ParentCategoryID>
        <ListOrder>10</ListOrder>
        <Lang>en-US</Lang>
        <CategoryName>mY SUB CATEGORY</CategoryName>
        <ParentName>By Technologies</ParentName>
        <CategoryDesc />
        <Message />
        <ProductCount>0</ProductCount>
        <ProductTemplate />
        <ListItemTemplate />
        <ListAltItemTemplate />
        <ImageURL />
        <SEOPageTitle />
        <SEOName />
        <MetaDescription />
        <MetaKeywords />
      </NB_Store_CategoriesInfo>
    </en-US>
  </categories>
</root>