I would ask myself "Is it mango first, then beer, or is it Belgian Beer first, then mango" and enter it accordingly. I.E. - Mango first would be in "fruit beer" and Belgian first would be in "Belgian Specialty".
Or you could enter it in both
Brewing since 1989 - BJCP National Rank
Fermenting: Saison Autome, Cherry Mead
Conditioning: Dortmunder Export, Belgian Dubbel, O-fest, Vienna Lager
On tap: CAP, Cider, Impy Cherry Stout, Rye Dunkel Bock, Belgian Chocolate Stout, Hopslam! Clone
Newly Bottled: Belgian Blonde, Belgian Quad