White Sidepipes

[66gtk]

After 2 failures with painting side pipes white, am at a total loss on what to do. On a car I'm working on the pipes were originally silver ceramic coated. After replacing the muffler section we decided it would look better white. The entire system was lightly media blasted to clean the areas very well. The VHT directions were followed perfectly and everything was done with white glove type accuracy (twice). 3 coats of VHT primer followed by 3 coats of VHT white following flash/recoat times, handling and cleaning procedures and wait times prior to curing on the car per directions and monitoring with infrared thermometer.

Both times, paint is holding and looking good - all except at the 4 into 1 collector area where it won't stay. Flaking and peeling off immediately after curing process. The rest of the pipes are perfect. This has become very time consuming and we consulted with a scientist over the phone with VHT and he confirms we are doing everything correctly. What gives? How are some of you able to keep this stuff on your collectors? The temp is MUCH MUCH lower than what the can states it is rated for, yet it won't hold up.

My only thought is that the ceramic coating has to be completely stripped for this to work? If so, why does it stick elsewhere where there was coating under the primer/paint. I figure a roughed up coating would be better than nothing, right?