Slide frame out, navigate to new page, slide frame back in

Just looking for some ideas on a good way to do this... basically I have a Frame in the middle of my window that loads various parts of the application in the form of Pages. So basically when someone clicks one of the buttons in my main menu, it just tells the frame to navigate to the relevant page.
So I want to make a nice transition effect instead of the new page just appearing, I want the frame to slide off to the left and then slide back in with the new page loaded.

My initial thought was to just create 2 storyboards, one for the sliding out animation and one for the slide back in, then handle the Storyboard_Completed event of the slide out storyboard and use that to tell my app to navigate to the new page and start the slide back in animation... but I don't know if maybe there is a cleaner/better way to do this without involving the code behind so much (the code behind is either going to have to create the storyboard 'withevents' so that I can handle the Completed event or its going to have to grab the storyboard defined in XAML using FindResource but then im not sure how to handle the event doing it that way)

Cheers
Chris