What Rathe said, but with the caveat that it will not work because of account authentication. The account you run the Shutdown command from on your PC will need to have rights to shutdown the WHS. You can accomplish this by going into the "Computer Management" on the WHS and adding your user account to the administrators group (probably don't want to do it this way for broader security reasons) or assigning the "Force shutdown from a remote system" user right to your account. The latter option gives you just what you're looking to accomplish without opening up other things that could have unintended consequences/security concerns.
To do this, on the WHS, go to Start-->Control Panel-->Administrative Tools-->Local Security Policy. In the left pane, expand Local Policies then click User Rights Assignment. In the right pane, find the setting for "Force shutdown from a remote system". Double-click this and then click the "Add User or Group..." button. Add the account you use from your system and hit OK twice. This will now grant your account the right to restart/shutdown the WHS from your client system.
To actually perform the shutdown, open notepad and enter the following:
shutdown /r /m \\SERVER /t 0
Replace SERVER with whatever your server name is. Save this file as RestartServer.cmd and that's it. Now you can just run RestartServer.cmd when you want to restart your WHS. If you want to make a shutdown version of this, just change the /r to /s.