Select node with child condition and parent condition

[wxdqz]

Here is my XML source file

<DeliverySchedule>
<Header>
<DistributorCode>MC</DistributorCode>
<TransmissionDate>2007-01-02</TransmissionDate>
<TransmissionTime>14:02:00.000</TransmissionTime>
</Header>
<Detail>
<StoreDelivery>
<SiteNum>001507</SiteNum>
<DSchedule>
<Order>
<Date>2007-09-02</Date>
<Time>08:02:01.000</Time>
</Order>
<Delivery>
<Date>2007-09-03</Date>
<Time>06:12:02.000</Time>
</Delivery>
</DSchedule>
<DSchedule>
<Order>
<Date>2007-09-04</Date>
<Time>08:02:03.000</Time>
</Order>
<Delivery>
<Date>2007-09-05</Date>
<Time>06:12:04.000</Time>
</Delivery>
</DSchedule>
</StoreDelivery>
<StoreDelivery>
<SiteNum>001510</SiteNum>
<DSchedule>
<Order>
<Date>2007-09-02</Date>
<Time>08:02:05.000</Time>
</Order>
<Delivery>
<Date>2007-09-03</Date>
<Time>06:12:06.000</Time>
</Delivery>
</DSchedule>
<DSchedule>
<Order>
<Date>2007-09-08</Date>
<Time>08:02:07.000</Time>
</Order>
<Delivery>
<Date>2007-09-09</Date>
<Time>06:12:08.000</Time>
</Delivery>
</DSchedule>
</StoreDelivery>
</Detail>
<Count>4</Count>
</DeliverySchedule>


I need to query the "Order" field or child where the field "Date" inside it is equal for example "2007-09-02" and its parent "SiteNum" = 001507. Can I do that? For example I did selectsinglenodes(Query) What can the query be? something like //Date[. =" . I don't know anyway can anyway help me with that.

This will really help me a lot, thank you