Dan, I spoke with an engine machinist, here was his suggestion to be done without removeing the engine or tearing it apart. Other fixes are a better resolution but necessitate striping the engine and remachining the seal register diameter:
With a new unused seal. Using a belt sander, carefully sand the outer diameter to remove the outer layer of rubber coating. Clean the seal carefully. Using a product such as "Hondabond" (used by Honda in lieu of gaskets, (available at their parts departments) coat the outer diameter of the seal (do not use a silicone). Clean and dry the area where the seal is to be installed so it is free of any
oil and dry. Berrymans Chemtool comes to mind here. Install the seal and then apply the same adhesive (Hondabond) around the outside of the seal face to complete the retention of the seal and effect a complete barrier for
oil seepage. You should end up with a clean seal face and a neat "Ring" of the adhesive that is visable around the outside diameter. When cured this should hold the seal in place.