JZ wrote an excellent profile on the style in an old issue of BYO (Jul/Aug 2008) but that article isn't on their website, drat them. I remember it being very worthwhile indeed. Perhaps a brewing pal has a back issue for you to read.
Here is another JZ/JP article with excellent information.
The best part of developing a new beer recipe is gathering and consuming the benchmarks. In this case, I'd start drinking De Koninck.
When you boil all the verbiage off of it, Belgian Pale Ale is essentially English Pale Ale or Special Bitter made in Belgium with Belgian ingredients. In this way it developed in precisely the same way American Pale Ale developed. Belgian Pale Ale tends to be less hops-forward, uses Continental ingredients, and is fermented with a Belgian yeast.
Developing a good Belgian Pale Ale recipe ought to be as simple as finding a well-regarded English Pale Ale or Special Bitter recipe and using that as a template. You'll need to swap some grist constituents in order to be true to style - Pils for pale ale base male, Caramunich or Caravienne for malt flavor and color. You'll need to swap out the Goldings for slightly less Saaz in the late additions. Finally, you'll need to use a comparatively subtle, well-attenuating and flocculant Belgian yeast strain. You want a star-bright, deep amber beer with a bit of noble hops character and present yet comparatively subdued yeast character.
The characteristics of Special B are out of place in this beer, except in very restrained amounts. If you already have some, use it, but don't exceed 4 oz in 5 gallons. I'd increase the Munich (since it's not Caramunich) to 2 lbs and reduce the pale malt accordingly.
Centennial is an atrocious choice for this style. See if you can't scare up something more "refined European" than "bossy, vulgar American."
US varieties derived from noble ancestors are perfect here: Liberty, Mt Hood, etc. If you MUST use Centennial, be very restrained on the flavor addition. In fact, I'd move the late addition to 20 minutes to make it more subtle.
Belgian Pale Ale is not a showcase for fruity-as-South-Beach-on-Pride-Day strains, even though it's Belgian. Select a somewhat restrained yeast with spicy notes. It should also quickly drop star-bright, which is a rare quality in a Belgian yeast. I adore Wyeast Ardennes in Belgian Pale Ale for those reasons: Flavor and clarity. That said, your White Labs Saison blend will likely work very well indeed. You'll probably have to wait a while for it to drop bright, unless you fine in a secondary.
Good luck!
Bob
