Modifying an extracted view for post layout simulation.

I am using IC 5.1.41 and Calibre 2010.4. I have an extracted view which is extracted by Calibre and I want to use it for post-layout simulation. When I modify the extracted view, Analog environment gives the following error:

ERROR: Netlister: the cellview **** was modified since last extraction.

Is there any way to modify an extracted view and use it for post layout simulation?

Thank you very much.