Here is a question for the people having this problem. Are any of you using the internal camera flash? if not where would the light come from if it is reflected from? The donut is a solution for internal flash problems.
In the case of the Simppu picture http://johan.kuvat.f...7.JPG?img=small the inter ring is the hole where the port body attaches and the outer ring is where the acrylic dome attaches to the dome backing plate. The only way to really attach the flocking paper to the dome backing plate is to disassemble the dome. This is easily done by removing the outer o-ring. However I do not recommend that anyone try this as re-assembly is quite difficult without a vacuum device.
The donut is a solution to eliminating any extraneous light emanating from behind the front of the lens, provided it is correctly fitted.
I see the solution to the reflection problem as a process of elimination, only once you have got rid of all other potential light sources except for reflective surfaces associated with the front of the lens, can you clearly establish the lens as being the source of the problem if the problem still exists. If it is the thin silver trim ring, then paint it out with a matt black paint and test again, it is one element in the source elimination methodology and until you apply a methodology you will be running in circles.
Problem solved. I heard (never saw) somebody were producing special blank-offs for the cases like this.
