Custom Membership Provider Using Additional Functions

I have built a custom membership provider that inherits from the MembershipProvider class. In my custom provider, I have defined a few new functions that I need to use, but my issue is that I can't access those functions on the front end using the Membership namespace.
So in my default.aspx code behind, I would like to call a function GetUserIDFromUserName() by just typing Membership.GetUserIDFromUserName().
In order for me to be able to do that right now, I have to cast Membership to my custom provider like this
Dim mem As ccMembershipProvider = CType(Membership.Provider, ccMembershipProvider)

In my web.config I have the following code
<membership defaultProvider="ccMembershipProvider"> <providers> <clear/> <add name="ccMembershipProvider" type="cc.Providers.ccMembershipProvider, cc" passwordFormat="Clea ...