You can manually opt-in to Microsoft Update (allowing installation of updates for other Microsoft products through Windows Update) through a simple script:

VBScript
ServiceManager = CreateObject("Microsoft.Update.ServiceManager")
ServiceManager.ClientApplicationID = "My App"
Set NewUpdateService = ServiceManager.AddService2("7971f918-a847-4430-9279-4a52d1efe18d",7,"")

Powershell
$ServiceManager = New-Object -ComObject "Microsoft.Update.ServiceManager"
$ServiceManager.ClientApplicationID = "My App"
$ServiceManager.AddService2("7971f918-a847-4430-9279-4a52d1efe18d",7,"")

Note that you probably need at least vers  ...