You want to use the aspnet_profile table or you want to create your own custom profile as in the link I provided.

I haven't actually tried the method in the link yet, but I have just added PropertyNames and Values into the aspnet_profile table.

If you want to go that route I can help you out but the other method that was in the link I provided I haven't done yet. It does seem easy to implement though. Basically it looks like they provide you with a sql script, then you just put in your database name and run it.  I'd imagine the script creates a profile table and either creates new stored procs or alters the current stored procs so you will also need to know what fileds you are going to want and add those into the sql scripts. Then, modify your web.config and your connection strings if you need to.

Let me know which method you are planning on using or if you have any questions. If I can't answer I'm sure someone else can

Thanks