SOPC Builder and nios ii help

Hi,

I am new to SOPC. I am trying to create my own component in SOPC and I am following steps which talks about how to add new component in sopc

I am following these steps :

1. In File tab in Sopc I created a new component and selected my Hdl files

2. I made adder_interface as top level

3. I verified interface signals and connections.

4. I could see the adder_interface as a component but when refresh component list it disappered.

Please help.