Remote connect to SQL Server Express 2008 is unreachable

Question

Hello,

I have a SQL Server Express 2008 on a machine, this could be XP, 7, 32/64bit.

I have configured the SQL for TCP/IP, NamedPipes etc...opened my router to forward the 1433 port from external to 1433 into my SQL Machine. A tool from forward.com seems to see my port correctly open. I drop my firewall just to make sure. But again no luck.

I use this connection string from inside my C# application and trying to reach the database.

Data Source=MY.WAN.IP\SQLEXPRESS;Initial Catalog=TheDb;User Id=sa;Password=apassword;

But after some tries i keep getting no connection into my SQL Server!

Any Ideas?