To implement/edit account lockout policy in Small Business Server do the following.
1. Start/Administrative Tools/Group Policy Management
2. Forest/Domains/<Your Domain>
3. Right-Click “Windows SBS User Policy” /Select “Edit”
4. Computer Configuration/Policies/Windows Settings/Security Settings/Account Policies/Account Lockout Policy
5. Double-Click the items in the right hand pane to enable and set the Account Lockout Parameters.