Opactiy Map/Transparency Issue

[JonWelch]

Hey everyone, so I'm hoping there may be a fix for this as I don't want to individually model every Hole of this Sieve. The issue I'm having is that I apply an opacity map to certain surfaces of this Filter to achieve the "porous" look that you see in the attached render. However when I render as a PNG with the transparency on, the "Holes" render the color of the Background that I set. This is particularly frustrating because I need to have those Holes transparent as I'm doing an animation with the piece that will later be in a video. The attachment shows that when I bring the PNG into Photoshop and apply a color on a separate layer in the background, that the Holes do not actually render as transparent.

Is there any way I can render those holes with transparency. I really would like to avoid modeling every hole.

Thanks.