"fft_lib not found" in ModelSim for FFT IP Megacore

Hi,

I've developed a project with QuartusII v.11.1 named "fft_hdlr" composed by a control module (fft_ctrl) and an instance of one FFT IP Megacore v.11.1 variant (fft_ip).

Now I want to simulate the project "fft_hdlr" in ModelSim-Altera using NativeLink.

For do this I've prepared a vhdl testbench and also in QII I've added to my project the file "fft_ip.qip" that QII v.11.1 (MegaCore Wizard) has generated for my "fft_ip" IP core variant (this file contains all the information related to files and library of the generated FFT IP core variant).

Launching from QII the RTL simulation, ModelSim starts but when arrives

to "elaborate" the file "fft_ip.vhd" (vhdl file of the FFT IP core) returns the error

"../fft_ip.vhd: Library fft_lib not found".

The library "fft_lib" is recalled inside the file fft_ip.vhd with the two lines:

library fft_lib;

use fft_lib.fft_pack_fft_111.all

I don't understand where is the problem and how to fix it !

Someone can help me ?

Thanks