Was thinking of that as well, but then I hate wheat beers, which is basically what a Roggenbier is :o( Maybe ill do it and just hop it up a bit more than normal?
Edit : Actually reading that recipe now its mainly Pils and Rye, this changes everything :o)
Acidulated malt aids in adjusting the ph of your mash. You don't need to use it in this recipe. It can be subbed with more lager malt. So can the wheat for that matter. I reckon that recipe would be kick ass with just the lager strain. Nice and tart. I reckon it'll be like Moa wheat on steroids!