xmloctopus

 function Set-EmailServerDetails([Parameter(Mandatory=$true)]$IISSite)
    {
        $EmailServerUserName = Retrieve-OctopusVariableIfExists -Name "EmailServerUserName";	
    	if ($EmailServerUserName -ne $null)
    	{
    		Set-WebConfigurationProperty -Filter "/system.net/mailSettings/smtp/network" -Name "userName" -PSPath $IISSite -Value $EmailServerUserName
    		Log "EmailServerUserName key has been updated";
    	}
    
        $EmailServerPassword = Retrieve-OctopusVariableIfExists -Name "EmailServerPassword";		
    	if ($EmailServerPassword -ne $null)
    	{
    		Set-WebConfigurationProperty -Filter "/system.net/mailSettings/smtp/network" -Name "password" -PSPath $IISSite -Value $EmailServerPassword
    		Log "EmailServerPassword key has been updated";
    	}
    }

function Retrieve-OctopusVariableIfExists([Parameter(Mandatory=$true)]$Name)
{
    if (Test-Path variable:global:OctopusParameters)
    {
        $Value = $OctopusParameters[$Name];
        if ($Value -ne $null)
        {
            Log-Debug "Octopus variable [$Name] is present"
            return $Value;
        }
        return $null;
    } 
    
    return $null;
}