Hack to get AccessToken for ARM from current PowerShell context

AzureRmAuth.ps1

# Working on 1.0.0 preview of Azure PowerShell cmdlets
function GetAccessToken(){
    $psContext = Get-AzureRmContext

    $context = [Microsoft.Azure.Common.Authentication.Models.AzureContext] $psContext
    $account = $context.Account
    $environment=  $context.Environment
    $tenant = $context.Tenant

    $authFactory = [Microsoft.Azure.Common.Authentication.AzureSession]::AuthenticationFactory

    $accessToken = $authFactory.Authenticate($account, $environment, $tenant.Id, $null, "Never")

    return $accessToken.AccessToken
}
function GetAuthorizationHeader(){
    $token = GetAccessToken
    return @{ "Authorization" = "Bearer $token"}
}


function GetSubscriptions(){
    $uri = "https://management.azure.com/subscriptions?api-version=2014-04-01"
    $headers = GetAuthorizationHeader
    $response1 = Invoke-RestMethod -Method Get -Uri $uri -Headers $headers
    $response1.value
}
function GetResourceGroups($subscriptionId){
    $uri = "https://management.azure.com/subscriptions/$subscriptionId/resourceGroups?api-version=2014-04-01"
    $headers = GetAuthorizationHeader
    $response1 = Invoke-RestMethod -Method Get -Uri $uri -Headers $headers
    $response1.value
}


$subscriptions = GetSubscriptions
$subscriptions

Write-Host ""

$resourceGroups = GetResourceGroups $subscriptions[0].subscriptionId
$resourceGroups