From the Server which is running Directory sync or Federated Services
Download and Install the Microsoft Online Services Module for Windows PowerShell:
http://community.office365.com/en-us/w/release-notes/312.aspx#Administration
From Powershell run the following:
#Connect to O365 Service
Connect-MsolService
#Use the logon name (UPN) in the following command to configure the password for a specific user to never change:
Set-MsolUser -UserPrincipalName <Account@Account.onmicrosoft.com> -PasswordNeverExpires:$true
Requires:
Office Sign-In Assistant: http://www.microsoft.com/en-us/download/details.aspx?id=41950
Azure Powershell Modules: http://go.microsoft.com/fwlink/p/?linkid=236297