Shelley, it's called seam tape and it appears what you are experiencing is fairly common. Some owners have carefully pulled the tape off, put it in a pan of hot water and reapplied (with caulk) by stretching it carefully. A
Trillium owner should probably give you step-by-step instructions.
Others, have removed the seam tape completely and filled the gap with caulk. Using a damp, scrunched up paper towel you could then apply "texture." Others just smoothed the caulk completely.
I like this treatment, after caulking the seams, hide them with paint!
http://www.fiberglassrv.com/forums/f...ams-26632.html
Here's some more links:
http://www.fiberglassrv.com/forums/f...html#post81612