Unable to get the Password using CrmMembershipProvider (Custom Membership) after Authenticating User without Login Control

HI,

I've implemented the Portal Website and using CRM 2011 as Backend Database. I've used the Custom Membership Provider i.e. CrmMembershipProvider It allows me to retrieve the Password when the User Login using Login Control but it won't allow me to retrieve password when I am enforcing automatic login when a new User Registers and Create new profile using our website. It is throwing error Parameter 's' cannot be null.

To Retrieve the Password, I am using MembeshipUser.GetPassword() method, Below is the config file setting