Mixed-signal CDL netlist export

Hi, 

I have a mixed-signal design and I want to export this in a CDL netlist format. I have seen through the documentation that there exists a Mixed-Signal Netlisting Mode option besides Digital and Analog options. However, I do not see that former option. What kind of tool should I install in order to see the option?

FYI: I am using Virtuoso IC6.1.8

Kind regards, 

Nicolas