PowerShell for creating TFS build definitions

I am working on a powershell script that will create TFS build definitions. I have used below example as my starting point.

http://geekswithblogs.net/jakob/archive/2010/04/26/creating-a-build-definition-using-the-tfs-2010-api.aspx

I have the script done in powershell and it creates me a build definition file in TFS. One thing I am stuck in is creating Process information such as "Item to build" and "Projects to build". The C# code for this is given below

//Set process parameters
varprocess = WorkflowHelpers.DeserializeProcessParameters(buildDefinition.ProcessParameters);

//Set BuildSettings properties
BuildSettings settings = newBuildSettings();
settings.ProjectsToBuild = newStringList("$/pathToProject/project.sln");
settings.PlatformConfigurations = newPlatformConfigurationList();
settings.PlatformConfigurations.Add(newPlatformConfiguration("Any CPU","Debug"));
process.Add("BuildSettings", settings);

buildDefinition.ProcessParameters = WorkflowHelpers.SerializeProcessParameters(process);

Below is the powershell code I have written to achive above.

Write-Host"Set process parameters "$now

$process=[Microsoft.TeamFoundation.Build.Workflow.WorkflowHelpers]::DeserializeProcessParameters($def.ProcessParameters)

Write-Host"Set build settings properties "$now

$settings=new-object-TypeNameMicrosoft.TeamFoundation.Build.Workflow.Activities.BuildSettings

$sList=New-Object-TypeNameMicrosoft.TeamFoundation.Build.Workflow.Activities.StringList

$sList="$/pathToProject/project.sln"

$settings.ProjectsToBuild=$sList

$process.Add("BuildSettings",$sList)

But the above does not create me the Build settings in my build definition file. Myquestion is am I doing this the correct way in powershell? I feel I am not writing the powershell code correctly as I am newbie to powershell. Any guidance and
help would be appreciated