How to run Toad as a different Windows user in Windows 7 (4303620)

I have to use different Windows Authentication credentials to connect to my SQL Server but when I choose Windows Authentication in the Connection Manager, it's grayed out. How can I run Toad as a different user?

** If you would like to transfer your connections when running Toad as a different user, do the following before launching Toad as different user:

1. Launch Toad as normal
2. From the Connection Manager, click the 'Export Connections' button
3. Check all relevant connections | Click 'Export'
4. Save 'My Connections.xml' file

Launch Toad as different user:

1. <Shift><Right Click> the Toad shortcut
2. Select 'Run as Different User'
3. When the Connection window displays, click the 'Import Connections' button and use the 'My Connections. xml' file saved previously.

In Vista and XP the <Shift> is not necessary