Thanks for all the commments.
Here is what iwas thinking about doing- since it's obvious that the water is penatrating betwwen the roof and the current sealant. I was planning to take a razor knife and cut back the sealant about a 1/4 inch to expose some new material to bond to and sand the adjacent alumn roof and then use a marine type deck caulk. The area in question is only about 12" long so while I'm sure the Eternabond is great I really don't want to redo the entire front cap at this point. Bear in mind the trailer is one year old and stored in a shed so the only UV and weather exposer is on trips. Good or bad idea?