验证活动目录中的过期密码

I'm writing a self service password reset system in c#, .Net 3.5 - one of the things that I need to do is allow users to authenticate with an expired password and give them the ability to change it. Can you, using the System.DirectoryServices or System.DirectoryServices.AccountManagement namespaces validate an expired password? Is there anyway to do it using low level api calls?I'm writing a self service password reset syste