How do Import products with categories from csv in magento 1.5

I am trying to import products into various categories from a csv. to get the format for the csv I have exported an existing product, there is a column with the heading _category, however the only category id listed is 0.

I have put the correct category ID in the csv for upload, however on import it complains that the category doesn't exist.

is there anything likely to cause this?

Below is the dataflow actions XML, is there anything i should be putting in here to make sure the category is exported/imported?

<action type="dataflow/convert_parser_csv" method="parse">
    <var name="delimiter"><![CDATA[,]]></var>
    <var name="enclose"><![CDATA["]]></var>
    <var name="fieldnames">true</var>
    <var name="store"><![CDATA[1]]></var>
    <var name="number_of_records">1</var>
    <var name="decimal_separator"><![CDATA[.]]></var>
    <var name="adapter">catalog/convert_adapter_product</var>
    <var name="method">parse</var>
</action>开发者_JAVA技巧