I would try to keep it in the low 60's as well. With the WB-06, you're dealing with more of a German Weizen yeast and not so much a Belgian Wit yeast. This yeast will be producing more clove and banana. I'm with Toga on this one, next time if you really need to use dry yeast, try the T-58 or the S-33. If you really want a good witbier, I would try to get your hands on the White Labs WLP400 Belgian Wit yeast or 410, you'll get a great wit using either of those.
Draft 1: Lightly smoked Weizen
Draft 2: Belgian Wit
Draft 3: Rauchbier
Primary 1: German Scwarzbier
On Deck: Belgian Brown Ale, Pale Ale, Stout