In the situation,how to creat a vcd file?

I am using "PLL Simulation Design Example" supported by Altera.I carried out all steps in the column"Using the Design Example".

Now I have to face the problem about how to creat a vcd file because I want to conduct power analysis .At first,I conduct the procedure as follows:Assignments-setting->EDA Tool Settings->Simulation->Generate Value Change Dump file script,then I assign the file name of VCD.But the vcd file is not created.

Then I try another method.A .wlf file is created by the modelsim software.So I think of converting the wlf file to vcd file.Even though ,I failed to creat the vcd file,maybe the commands are not used corretly.

I serched the answer to the quertion in the website,but I can't realize those solutions.Who can solve the problem related to the design example?

Detailed steps are appreciated!

Thanks!