Autounattended.xml & GPT partitions

We are trying to setup an unattended install of windows 7 to a gpt partition on a Lenovo U410, which has UEFI bios.

This webpage outlines how to format the disk for GPT. If add the default configuration, from the page, to the autounattended.xml file I get the error:

Windows cannot be install to this disk. The selected disk is of GPT partition style.

If we use the, webpage's, recommended configuration from the above page we get an 0x00042465 (VDS_S_EXTEND_FILE_SYSTEM_FAILED) error, outlined here

This is our xml file:

<?xml version="1.0" encoding="utf-8"?>
<!--This answer file generated by RT Seven Lite-->
<unattend xmlns="urn:schemas-microsoft-com:unattend">
  <settings pass="windowsPE">
    <component name="Microsoft-Windows-International-Core-WinPE" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="NonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
      <SetupUILanguage>
        <UILanguage>en-US</UILanguage>
      </SetupUILanguage>
      <InputLocale>0409:00000409</InputLocale>
      <UserLocale>en-GB</UserLocale>
      <UILanguage>en-US</UILanguage>
      <SystemLocale>en-US</SystemLocale>
    </component>
    <component name="Microsoft-Windows-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="NonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
        <!-- Lifted from Document http://msdn.microsoft.com/en-us/windows/hardware/gg463140.aspx -->
        <DiskConfiguration>
          <Disk wcm:action="add">
            <DiskID>1</DiskID> 
            <WillWipeDisk>true</WillWipeDisk> 
            <CreatePartitions>

              <!-- System partition (ESP) -->
              <CreatePartition wcm:action="add">
                <Order>1</Order> 
                <Type>EFI</Type> 
                <Size>260</Size> 
                <!-- Note: for Advanced Format Generation One drives, change to size=260 -->
              </CreatePartition>

              <!-- Microsoft reserved partition (MSR) -->
              <CreatePartition wcm:action="add">
                <Order>2</Order> 
                <Type>MSR</Type> 
                <Size>128</Size> 
              </CreatePartition>

              <!-- Windows partition -->
              <CreatePartition wcm:action="add">
                <Order>3</Order> 
                <Type>Primary</Type> 
                <Extend>true</Extend> 
              </CreatePartition>
            </CreatePartitions>

            <ModifyPartitions>

              <!-- System partition (ESP) -->
              <ModifyPartition wcm:action="add">
                <Order>1</Order> 
                <PartitionID>1</PartitionID> 
                <Label>System</Label> 
                <Format>FAT32</Format> 
              </ModifyPartition>

              <!-- The MSR partition does not need to be modified -->

              <!-- Windows partition -->
              <ModifyPartition wcm:action="add">
                <Order>2</Order> 
                <PartitionID>3</PartitionID> 
                <Label>Windows</Label> 
                <Letter>C</Letter> 
                <Format>NTFS</Format> 
              </ModifyPartition>
            </ModifyPartitions>
          </Disk>
          <WillShowUI>OnError</WillShowUI> 
        </DiskConfiguration>
      <ImageInstall>
        <OSImage>
          <InstallFrom>
            <MetaData wcm:action="add">
              <Key>/IMAGE/NAME</Key>
              <value>Windows 7 ENTERPRISE</value>
            </MetaData>
          </InstallFrom>
           <InstallTo>
            <DiskID>1</DiskID>
            <PartitionID>3</PartitionID>
          </InstallTo>
          <InstallToAvailablePartition>false</InstallToAvailablePartition>
          <WillShowUI>OnError</WillShowUI>
        </OSImage>
      </ImageInstall>
      <UserData>
        <ProductKey>
          <Key>Some-Funky-Key</Key>
          <WillShowUI>OnError</WillShowUI>
        </ProductKey>
        <Organization>MyCompany</Organization>
        <FullName>Cowboy</FullName>
        <AcceptEula>true</AcceptEula>
      </UserData>
    </component>
  </settings>
  <settings pass="oobeSystem">
    <component name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="NonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
        <UserAccounts>
            <LocalAccounts>
                <LocalAccount wcm:action="add">
                    <Name>Cowboy</Name>
                    <Group>Administrators</Group>
                    <Password>
                        <PlainText>true</PlainText>
                        <Value>Indian</Value>
                    </Password>
                </LocalAccount>
            </LocalAccounts>
        </UserAccounts>
        <OOBE>
            <NetworkLocation>Work</NetworkLocation>
            <HideEULAPage>true</HideEULAPage>
            <HideWirelessSetupInOOBE>true</HideWirelessSetupInOOBE>
        </OOBE>
        <DisableAutoDaylightTimeSet>false</DisableAutoDaylightTimeSet>
        <TimeZone>GMT Standard Time</TimeZone>
        <AutoLogon>
            <Password>
                <Value>Indian</Value>
                <PlainText>true</PlainText>
            </Password>
            <Domain>.</Domain>
            <Enabled>true</Enabled>
            <LogonCount>1</LogonCount>
            <Username>bromine</Username>
        </AutoLogon>
    </component>
  </settings>
  <settings pass="specialize">
    <component name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="NonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
      <ComputerName>RENAME_ME</ComputerName>
    </component>
    <component name="Microsoft-Windows-Security-Licensing-SLC-UX" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="NonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
      <SkipAutoActivation>true</SkipAutoActivation>
    </component>
  </settings>
</unattend>

As I said it's pretty much lifted from the TechNet webpage listed above. Any help would be greatly appreciated.

Should this be on SuperUser?