Netlist based component

Hi

I made a simple VGA Hardware Accelerator component with the help of the Component Editor in SOPC builder 5.0, I use this component with the Nios II processor. The VGA was developed using VHDL. My question is how to create a netlist based component, for example like the Nios II processor, how can I convert my existing VGA component to a netlist based component or something like that, so that the VHDL files can not be accessed. Now my VGA component is visible in the component library in SOPC Builder and it can be added to a system, this is ok, but the VHDL files can be located in the component folder where the component is located, and that is not preferable.

Thank you in advance