Form Based Authentication with Active Directory

Dear Community,

we are planning to change the Windchill Authentication to Form Based Authentication.
Windchill is connected to the Active Directory of the customer as well.
How does the configuration look like in the tomcat settings? Does anybody have an example? 

We have entered in the server.xml the Realm entries as below (but we are not sure about how the Active Directory entry look like):

In the web.xml file:

Thanks in advance.