How to access the methods and properties of a custom Provider

[motf]

I have created a custom provider called FileSystemProvider which is
derived from ProviderBase. The Provider is initialized in the
web.config using its Initialize method.
My problem is that I do not know how to access the properties and
methods of my provider.
I know that I can access the methods of a Membershipprovider by using
System.Web.Security.Membership.XXX but how do I access a custom
provider.

with regards

Werner Fallnit