Big D
I don't want to rain on your parade, But if your making a Wit you HAVE to have the belgian wit strain of yeast. Nothing else is acceptable, the flavour profile of a wit is largely based on the yeast, it is a good attenuator but an extremely poor flocculator and heaps of the yeast is left in suspension, and I mean heaps it never really clears.
If you do this beer with a normal ale yeast I think you will be very disappointed with the results, and believe me this is one beer where the yeast makes all the difference, it is very noticable.
Sorry for the rant Big D, but this is a fantastic beer, it would be a shame if it was dissapointing. Why not give ESB a call Mel has the Begian Wit II in stock, it's worth the extra expense.
Regards
Witless Andrew