Strangely enough I have added orange juice in the secondary; a 1/2 gallon to be precise. Did this in a "Beer Captured" recipe for Fantom. Do a search on HBT for a Fantom thread where I posted the recipe. The base was a beer containing some small % of wheat malt, 1 lb or so.
It worked out quite well a good beer, but without ever having Fantom I have no idea how close it came to the original. Remember to add pectic enzyme so that the beer will clear.
Relax, don't worry etc. and so on.
Primaries: Old Ale, Barleywine, ESB, Scottish 80/.
Secondaries: Lime Wine, Strawberry-Banana Mead, Carmenere (from 144 lbs of grapes!), Engl. Barleywine, Modded JOAM, Concord Grape Pyment.
Kegs: Choc/Coffee Stout, Saison, Dry Stout.
Bottles: Belgian Str. Dark, Dubbel, Cider X 2, Modded JOAM, RJS Pinot Noir, RJS Aussie Cab. Sauv.
Coming soon: Blueberry Mead.