Transparency Maps Revisited

I have continued testing using animated gradient transparency maps to create the bursting bubble effect. One thing I have attempted is to layer the transparency of the bubble's shader witht the transparency of the gradient. I tried this by using Maya's "Mult Double" node. I created three of these nodes, connected the out colour of the gradient into their inputs & connected their outputs to the colour of the shader as illustrated below.

 This however didn't give the desired results as shown below.

 As you can see, the part of the bubble which has burst is not fully transparent.

Another test I did was to see if I could solve the problem of the specular highlight showing up in the transparent areas. I tested this on the Mental Ray shader "mia_material_x". This proved to be more successful.

 I acheived this by simply using the "Reverse" node in Maya to invert the colours of the gradient so that it would only show the specular highlight on the side of the bubble which is still visible.