Profiles to add additional Information

 Hi,
I've used the asp.net login to setup my login and registration feature. Only thing is I also need a full Name for each user.
I read that a good and "easy" way of doing this is using Profiles.
I have tried to do this in the following way.
web.config
    <profile>
      <providers>
        
      </providers>

      <!-- Define the properties for Profile... -->
      <properties>
        <add name="UserFullName" type="String" serializeAs="String" />
      </properties>
    </profile>
The code I am using is: 
protected void ...