Here is how to import G code and Verify against an STL file.....
The G Code must pretty generic Fanuc stuff.
First you have to add the button that will allow you to import an nc file to an operation. Open your operations manager and double click in the blank area to the right of the buttons. Add the "Import NC file" button.
Then click on that button and follow the prompts to upload the ncc file.
Then, to the setup you have the new operation in and load your STL file as your stock.
Then just run Verify...Its that easy!
I have attached some screen shots to help.