Hello Marcus
To activate the experimental features, just open the ks9settings.xml from the resources folder with a notepad. Then search for "experimental" and change the value from false to true. (<experimental_features bool="true"/>)
Then start KeyShot.
In the attached KSP, you'll see two solutions.
I've splitted the cap into separated objects (inner and outer shape) and applied different materials.
And I've splitted the cap to get just a single surface (without thickness). This part has a metal and a paint on top. As you can see, there's a "ray mask" node applied on the opacity of the labels. This ray mask ist an experimental feature and do the job right. A backside mask with an invert (utility) node would work as well, but ray mask is one node simpler.
Hope that helps
Cheers
Marco