For Windows to retreive updates from Microsoft Update, as opposed to Windows Update (which is the default), you have to opt in. This is usually done through the Windows Update GUI by selecting “Get updates for other Microsoft Products”:

This becomes tedious very quickly so here’s how you can do it with PowerShell:

https://gist.github.com/morgansimonsen/8039966

To see if this was successful you can query the Services property of the $MU object:

$mu.Services

You should see something like this:

Name                  : Microsoft Update
ContentValidationCert : {}
ExpirationDate        : 11/18/2014 1:27:43 AM
IsManaged             : False
IsRegisteredWithAU    : True
IssueDate             : 11/18/2011 1:27:43 AM
OffersWindowsUpdates  : True
RedirectUrls          : System.__ComObject
ServiceID             : 7971f918-a847-4430-9279-4a52d1efe18d
IsScanPackageService  : False
CanRegisterWithAU     : True
ServiceUrl            : https://fe1.update.microsoft.com/v6/
SetupPrefix           : mu
IsDefaultAUService    : True

Name                  : Windows Update
ContentValidationCert : {}
ExpirationDate        : 6/18/5254 9:21:00 PM
IsManaged             : False
IsRegisteredWithAU    : False
IssueDate             : 1/1/2003 12:00:00 AM
OffersWindowsUpdates  : True
RedirectUrls          : System.__ComObject
ServiceID             : 9482f4b4-e343-43b6-b170-9a65bc822c77
IsScanPackageService  : False
CanRegisterWithAU     : True
ServiceUrl            :
SetupPrefix           :
IsDefaultAUService    : False

If you only have the Windows Update entry something went wrong.

One of the major benefits of this is that you can do it remotely. I have yet to find another way to do this. If you know, leave a comment.