How to manually instantiate the generated memory model for Qsys testbench?

Dear all, it says here

http://www.altera.com/support/kdb/solutions/spr375501.html

When you attempt to generate a DDR with ALTMEMPHY design with Qsys and set the create testbench qsys system option to any value other than none, the system fails to connect a memory model to the Qsys-generated testbench.

we need to manually instantiate the generated memory model (<instance_name>_mem_model.v/.vhd) in the Qsys-generated testbench (<instance_name>_tb.v/.vhd) .

But how to manually instantiate the generated memory model? what name should be used for the instantiation? anyone have examples?

Thank you very much!