MembershipProvider is not marked as serializable?

Hi everyone,

I have created a custom membership provider and set the serializable
declaration on it, but for some reason i am still getting an error
message saying

"Type 'System.Web.Security.MembershipProvider' in Assembly
'System.Web, Version=2.0.0.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a' is not marked as serializable. "

Does anyone know why? Is the MembershipProvider base class not
serializable? Is there anyway of doing this?