Has anyone had any experience with these fasteners (white nylon, 2 part, female grommet which attaches to sheetmetal, male end attached to panel)? I had to remove the A pillar trim and couldn't separate the the 2 parts of the fastener without breaking the grommet even with a std. fastener removal tool. I bought spares, so no big deal, but just wondered if there was a trick to taking them apart without breaking them.