How do you install powershell-ise on a Windows Server 2012 R2 Core?

HI,

I'm trying to install WSUS on a Windows 2012 R2 Core using powershell exclusively as kind of a learning experience. I've hit a snag in that the guide i was following uses Powershell-ise. I've been unable to figure out how to install powershell-ise on this server. I repeatedly get the following:

PS C:\Windows\system32> Install-WindowsFeature -Name powershell-ise
Install-WindowsFeature : The request to add or remove features on the specified server failed.
Installation of one or more roles, role services, or features failed.
The source files could not be downloaded.
Use the "source" option to specify the location of the files that are required to restore the feature. For more
information on specifying a source location, see http://go.microsoft.com/fwlink/?LinkId=243077. Error: 0x800f0906
At line:1 char:1
+ Install-WindowsFeature -Name powershell-ise
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (@{Vhd=; Credent...Name=localhost}:PSObject) [Install-WindowsFeature],
    Exception
    + FullyQualifiedErrorId : DISMAPI_Error__Cbs_Download_Failure,Microsoft.Windows.ServerManager.Commands.AddWindowsF
   eatureCommand

Success Restart Needed Exit Code      Feature Result
------- -------------- ---------      --------------
False   No             Failed         {}

Can anyone tell me what i should have the -source parameter set to?

thanks