Transparency issues in Viz5?

[performlabrit]

Here is a snippet of code that produces different results in Viz4 and Viz5.

It works correctly in Viz4, producing a semi-opaque green box with 1 red side. In Viz5, it produces a black box (no transparency).

self.standingBox = vizshape.addBox( boxSizeInfo,alpha = 0.7,color=viz.GREEN,splitFaces = True,back=True)
self.standingBox.disable(viz.CULL_FACE)