Hog 4 Fixture Builder Question

Am I limited in the fixture builder? By that I mean are there things I simply can't recreate in the fixture builder, are there some things I just have to have built for me by High End?

I had to create a fixture the other day and was having a hard time with it. I was trying to build an updated fixture based on outdated version that was in the fixture library. I couldn't seem to get my fixture to work even though I was mimicking the original version. It wasn't until I built it starting with the old version as a base that I was able to make it work.