Jeff is correct. Sean did produce a Pastel Super from breeding a Pastel Sulfur to a Fire. So far the creations that I have seen with both mutations appear to be the same as an end result. i.e. a Pastel Fire looks almost identical to a Pastel Sulfur and so forth.
I myself am hoping that the Super Sulfur will have a greater tendency to produce Supers with more yellow. However, I don't think enough Super Sulfurs have been produced to make a claim like that yet. I mssed on Super SUlfurs last year, and am cooking another clutch this year. Hopefully I can hit one or two.