How can I run a PowerShell script during the specialize pass of a WDS deploy?

I'm setting up Windows Deployment Services (WDS) for Windows Server 2012 unattended deployments using the default boot.wim file found on the install media. I have a PowerShell script that performs automated customisations for our site. I want this script to be run during the specialize pass, so I don't have to mess about with auto logins and to be able to save myself a reboot during provisioning. The script doesn't appear to run and the logs only give an unhelpful error code.

Here is the relevant part of my unattend file:

    <settings pass="specialize">
        <component name="Microsoft-Windows-Deployment" 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">
            <RunSynchronous>
                <RunSynchronousCommand wcm:action="add">
                    <Order>1</Order>
                    <Credentials>
                        <Domain>WDSSERVER</Domain>
                        <Password>APASSWORD</Password>
                        <Username>AUSERNAME</Username>
                    </Credentials>
                    <Path>"c:\windows\system32\windowspowershell\v1.0\powershell.exe" -executionpolicy unrestricted -command "\\<REMOTESERVER>\reminst\customize\specialize.ps1"</Path>
                </RunSynchronousCommand>
            </RunSynchronous>
        </component>
    </settings>

In response to request from kce. Here's the script itself:

write-host "Executing customisation script."
write-host "enabling powershell script execution"
Set-ExecutionPolicy Unrestricted

write-host "Bringing non-system disks online..."
Get-Disk | Where-Object IsOffline –Eq $True | Set-Disk –IsOffline $False
Set-Disk -Number 1 -IsReadOnly $False
Set-Disk -Number 2 -IsReadOnly $False

write-host "Setting up NTP..."
W32tm /register
start-service w32time
w32tm /config /manualpeerlist:uk.pool.ntp.org
restart-service w32time
Set-Service W32Time -StartupType Automatic
sc triggerinfo w32time start/networkon stop/networkoff
sc config W32Time start=auto

write-host "Determining system RAM and setting pagefile..."
$RAM = Get-WmiObject -Class Win32_OperatingSystem | Select TotalVisibleMemorySize
$RAM = ($RAM.TotalVisibleMemorySize / 1kb).tostring("F00")
write-host "disable automanage"
wmic computersystem set AutomaticManagedPagefile=False
Write-Host "removing old pagefile"
wmic pagefileset delete
write-host "creating new pagefile on E:\"
wmic pagefileset create name=“e:\pagefile.sys”
write-host "set size"
$PageFile = Get-WmiObject -Class Win32_PageFileSetting
$PageFile.InitialSize = $RAM
$PageFile.MaximumSize = $RAM
[void]$PageFile.Put()

write-host "Disabling Windows Firewall..."
netsh advfirewall set allprofiles state off

write-host "Enabling powershell remoting..."
Enable-PSRemoting -Force

write-host "Sorting out remote management trusted hosts..."
winrm s winrm/config/client '@{TrustedHosts="*"}'

write-host "Disabling Windows error reporting..."
Disable-WindowsErrorReporting

write-host "Installing VMware Tools..."
c:\vmware-tools.exe /S /v"/qn"

From what I'm reading, an uncaught throw results in the exit code being one. Also, you're passing in the script path through the -command switch, when it should be passed through the -file switch; see the reference. -command will treat your string as a command and since it's a file path, it will throw one of those same red-letter exceptions we love in the PowerShell window, and voila! Exit code 1 since the exception is uncaught. All that is speculation of course, unless

"powershell.exe" -executionpolicy bypass -noprofile -file "\\<REMOTESERVER>\reminst\customize\specialize.ps1"

actually works, assuming the account it's running under has permissions to the fileshare. To avoid those permission issues you could just paste the code in the answer file between {} and then you would use the -command option,

"powershell.exe" -executionpolicy bypass -noprofile -command {...}