the sku filter applies but on the xml is not written
<?xml version="1.0" encoding="UTF-8"?>
<export>
<product>
<virtuemart_product_id><![CDATA[2731]]></virtuemart_product_id>
<product_customsku><![CDATA[]]></product_customsku>
<product_sku><![CDATA[]]></product_sku>
<product_mpn><![CDATA[]]></product_mpn>
<product_gtin><![CDATA[]]></product_gtin>
</product>
<product>
<virtuemart_product_id><![CDATA[35253]]></virtuemart_product_id>
<product_customsku><![CDATA[07.049.003334]]></product_customsku>
<product_sku><![CDATA[]]></product_sku>
<product_mpn><![CDATA[222182002260]]></product_mpn>
<product_gtin><![CDATA[5204850233334]]></product_gtin>
</product>
<product>
<virtuemart_product_id><![CDATA[50576]]></virtuemart_product_id>
<product_customsku><![CDATA[43.008.50149440]]></product_customsku>
<product_sku><![CDATA[]]></product_sku>
<product_mpn><![CDATA[5212058625240]]></product_mpn>
<product_gtin><![CDATA[3065]]></product_gtin>
</product>
</export>