What kind of analysis are you doing? I suspect that you could do this with envlp analysis - but to be honest, you've not given much info as to what you're trying to simulate or how you're trying to simulate it.
Don't know, sorry. Maybe somebody else can answer this (I might be able to make a suggestion if I was more familiar with the details of your system). Perhaps contacting customer support for advice would be a good idea, then we can take a look at what you're doing in more detail?