Just want to add "Full Name" to existing membership

I am using SQL membership provider and have everything in place and working. I don't want to change what already exists, I just want to "extended" what is already there. For example, lets say I want to create another Table in my SQL database call UserProfileData (UPD for short). And the table will contain the UserID (uniqueidentifer) and FullName nvarchar(50). I then want to know what is the least amount of coding I need to do so that in my application I can use the membership object to get and set the Full Name  property like so....

Membership.GetUser().FullName = 'John Does' ;

 Do I have to write every method of the provider class just to add a single property?

Now I really want to figure out a way to be able to add any column to the UPD table and reference properties with the ...