Conditionally specifying switch parameters in PowerShell

I'm writing a PowerShell script that uses the SharePoint 2010 New-SPWeb cmdlet to create sites defined by an Xml file:

<?xml version="1.0" encoding="utf-8" ?>
<siteStructure>
  <site>
    <url>Corporate</url>
    <name>Corporate</name>
    <language>1033</language>
    <addToQuickLaunch>0</addToQuickLaunch>
    <addToTopNav>0</addToTopNav>
    <useParentTopNav>1</useParentTopNav>
  </site>
</siteStructure>

The New-SPWeb cmdlet has three switch parameters:

1. AddToQuickLaunch
2. AddToTopNav
3. UseParentTopNav

I'm having trouble figuring out how to only set the switch parameter when the matching value in the Xml is 0 or $true.

It's almost like I need some sort of inline-if syntax when calling New-SPWeb to set the three switch parameters.

$siteStructureData = [xml](Get-Content .\Data-SiteStructure.xml)

# find the template to use
$webTemplate = Get-SPWebTemplate | Where {$_.Title -like $templateName } 

if ($webTemplate)
{
    # iterate through and create sites
    foreach ($siteToCreate in $siteStructureData.siteStructure.site)
    {   
        "Creating site $webtitle at $URL/$webUrl"

        # http://technet.microsoft.com/en-us/library/ff607579.aspx
        New-SPWeb `
            -Url "$URL/$siteToCreate.url" `
            -Name $siteToCreate.name `
            -Template $webTemplate `
            -Language $siteToCreate.language 
            # set -AddToQuickLaunch
            # set -AddToTopNav
            # set -UseParentTopNav
    }
}
else
{
    throw ("Could not find template $templateName");
}

Many thanks!