Quote - There most certainly is a way around it - you just said it - AO should involve the shader transparency channel if it is in use. This is a pretty simple thing to do, and it is exactly what is done by the ray-tracing directional shadow generator. There's no reason why the AO shadow generator cannot send its ray out and query the shader at the intersection point.

You misunderstood, all i'm saying is that it's not a 'bug' but rather a limitation of Firefly. SM can of course add new code to give us this feature, in which case it would no longer be 'Ambient Occlusion' but rather 'Shaded Occlusion' (or Final Gathering as other renderers call it) Which is vastly superior then AO, but comes at a significant performance loss in REYES. Not that i would mind if they added it of course as it can be used for all sorts of neat tricks, including multi bounce IBL and color bleeding to name just 2.

Also note that kerkythea does Final Gathering by default (as you can see in it's render options) It can also do path tracing, which gives you physically correct occlusion. Neither of these options are available in firefly, till SM actually go and add them in the code.

EDIT: See here