I am trying to convert an XML catalogue from one xml format to another.
I receive the catalogue in the format below.
It is in two parts a list of items and a list of product questions (ProdQU) with there answers (ProdAn).
There are a maximum of two questions per item.

<Catalogue>
<Item id = “101”>
<ProdQu="1002"/>
</Item>
<Item id = “102”>
<ProdQu="1002"/>
<ProdQu="1003"/>
</Item>

<Question ProdQu ="1002" Descriptor="Wall colour" >
        <Option ProdAn ="20003" Value=" Green" "/>
        <Option ProdAn ="20004" Value=White"/>
</Question>
<Question ProdQu ="1003" Descriptor="Number of doors" >
        <Option IDAn="20005" Value="two doors"/>
    <Option IDAn="20006" Value="four doors/>
        <Option IDAn="20007" Value="six doors/>
  </Question>
< /Catalogue >

I want to end up with the XML format below.
With the items with a list of  sub categories (subcat) that are made up of the itemID with every possible question answer combination in the following format.
itemID_ProdQU_ProdAn
or
itemID_ProdQU_ProdAn_ProdQU_ProdAn


< Catalogue >
<item ID = 101>
<SubCat>101_1002_20003</subCat>
<SubCat>101_1002_20004</subCat>
</item >
<item ID = 102>
<SubCat>102_1002_20003_1003_20005</subCat>
<SubCat>102_1002_20003_1003_20006</subCat>
<SubCat>102_1002_20003_1003_20007</subCat>
<SubCat>102_1002_20004_1003_20005</subCat>
<SubCat>102_1002_20004_1003_20006</subCat>
<SubCat>102_1002_20004_1003_20007</subCat>
</item >
< Catalogue >
I have tried doing this with tFileInputXML's and tMaps but cannot get it to work.
Thanks for any help.