Our xBs have beam rear axles but no factory adjustment for camber. Using lowering springs will affect rear camber but usually not enough to worry about it. A few people on this forum have used plastic camber shims to get the rear wheels back to factory spec after lowering, but the rest of us just live with it.
See this thread:
http://www.newscionxb.com/133-wheels-tires/9432-rear-alignment-problem.html
See this thread:
http://www.newscionxb.com/133-wheels-tires/9432-rear-alignment-problem.html