Hello, Leyla!
Celebrating a birthday while in Walt Disney World is so very special, especially if celebrating with a favorite character! Wow!
When I called Walt Disney World to inquire about
specialty cakes at other resort locations, I was later emailed a PDF which included photos of the cake options from which Guests can choose. While I haven't personally seen the Jake the Neverland Pirates cake design, I have seen other character images on such cakes, both in that PDF as well as on the unofficial website wdwmagic.com as well as one of my personal favorites, disneyfoodblog.com. On the latter website, simply enter "disney world restaurant birthday treats" into the search bar and click on the blog posted on September 1, 2009. Scroll down and you'll see many photos of lots of gorgeous cakes of many varieties; I'm sure you'll be impressed by the variety and quality of all of them. The cake you're thinking of ordering is sure to be just as fantastic, too!
I hope this helps!
Have a wonderful birthday celebration, and be sure to wish your little pirate a very happy birthday from the Walt Disney World Moms Panel, too! :-)