If yours are like mine, look for a small slot near the top of the plastic retainer. Place a straight blade screwdriver in the slot and pry up a little bit. After it tries to release, push the retainer up from below and it should pop right off. Sorry I don't have any picture because The Silver Otter is over at the shop getting her NEW Dometic installed.
Greg Heuer, Spirit of Virginia Airstream Club
2011 31' Classic Ltd. - The Silver Otter III
2013 GMC Denali 2500HD 6.6 DuraMax - Sierra Blanca
TAC VA-18 | ACI 1927 - Spirit of Virginia Club | AIR 53869