Boost XML - get next node

The following code attempts to get data from an xml file and add it to a custom SensorConfiguration class, and then add that to a map of these SensorConfigurations

My problem is that it always takes the first sensor configuration in the second foreach loop. I know why, but I don't know the correct syntax, and I'm not sure how to google this.

Here's the XML:

<?xml version="1.0" encoding="utf-8"?>
<root>
<sensorconfigurations>
    <configuration>
        <name>SensorConfiguration1</name>
        <sensorid>1</sensorid>
        <signalindex>1</signalindex>
        <mappingscheme>mappingscheme1</mappingscheme>
        <soundpack>test1.wav</soundpack>
    </configuration>
    <configuration>
        <name>SensorConfiguration2</name>
        <sensorid>2</sensorid>
        <signalindex>2</signalindex>
        <mappingscheme>mappingscheme1</mappingscheme>
        <soundpack>test2.wav</soundpack>
    </configuration>
    <configuration>
        <name>SensorConfiguration3</name>
        <sensorid>3</sensorid>
        <signalindex>3</signalindex>
        <mappingscheme>mappingscheme2</mappingscheme>
        <soundpack>test3.wav</soundpack>
    </configuration>
</sensorconfigurations>
</root>

Here's the entire function constructor-method:

SensorConfigurationBank::SensorConfigurationBank()
{   
string m_level;
using boost::property_tree::ptree;
ptree pt;
read_xml("SensorConfigurationBank.xml", pt);
BOOST_FOREACH(ptree::value_type &v,
    pt.get_child("root.sensorconfigurations"))
{
    SensorConfiguration newSensorConf;
    BOOST_FOREACH(ptree::value_type &w,
        pt.get_child("root.sensorconfigurations.configuration"))
    {
        if(w.first == "name")
        {
            newSensorConf.setName(w.second.data());
        }
        if(w.first == "sensorid")
        {
            string stringToInt = w.second.data();
            istringstream iss(stringToInt);
            int value;
            iss >> value;
            newSensorConf.setSensorID(value);
        }
        if(w.first == "signalindex")
        {
            string stringToInt = w.second.data();
            istringstream iss(stringToInt);
            int value;
            iss >> value;
            newSensorConf.setSignalIndex(value);
        }
        if(w.first == "mappingscheme")
        {
            newSensorConf.setMappingScheme(getMappingScheme(w.second.data()));
        }
        if(w.first == "soundpack")
        {
            newSensorConf.setSoundPack(w.second.data());
        }
    }
    sensorConfigurations_.insert(make_pair(newSensorConf.getName(), newSensorConf));
}
//save();
}

I know it's slightly incomprehensible, but here's the important part:

BOOST_FOREACH(ptree::value_type &w,
        pt.get_child("root.sensorconfigurations.configuration"))

Instead of getting the specific child 'configuration', I want it to get to the child that the first loop is looking at, so it looks at configuration #2 instead of getting configuration #1 up to an infinite number of times.

It's basically just the last line of code I pasted above that needs to be changed somehow, then I think it will work! Thanks in advance.