You would hook up your Gemini2 like any other ASCOM based mount.
It would not use the built in planetarium within Gemini2 although there is nothing to keep you from using it to point at a target.
The planetarium in Voyager functions in two ways. First, it is used as a way to find the coordinates of objects. Second is less obvious at first but it is also used to find appropriate stars for use in focusing when doing single star focusing as opposed to local field. You will want to do that at least once when initially setting up focus for Voyager.
For that purpose, you can get any of a number of free planetarium programs that are out there, and it should work just fine with Gemini 2.
You can actually dry run much of this in daylight without even using the 45 days trial. When you install Voyager, it comes up as follows:
Instead of choosing to activate the trial, simply choose demo mode. There are a number of things you cannot do in demo mode (such as run drag script), but there is a lot of initial setup/testing you can do.
In fact, I keep a version of Voyager on my Desktop that hasn't been activated (I have purchased the program), simply so I can bring it up and help with various questions about the program without accessing the computer in my observatory.
Bottom line is I am basically positive you can get this to work with Gemini 2, but you probably will want to install a separate (and free) planetarium program so that Voyager can find single stars to use for focusing.