How do I enable forms-based authentication in Entourage?

In Entourage, on the Tools menu, click Accounts.
Select the Exchange account, and then click Edit.
Make sure that Entourage is pointing to your front-end server. On the Account Settings tab, in Exchange Server, the name of the front-end server should be listed.
On the Advanced tab, make sure that the DAV service requires secure connection (SSL) check box is selected.

Once that setting is in place,close Entourage and re-open it. If you are prompted for your credentials enter your BlazerID and password. This should resolve the problem.