I was watching an episode of Sex and the City last night, when Carrie's ex-editor came out of a liquor store with an enormous bottle of gin, pissed about a publisher dropping a talented author, and couldn't help but think of you. ;-)
Well, to the issue in question: my novel is not in linear format. Quite a good bit is told in flashback via dialogue, dreams or... well, flashback.(Hell, one entire chapter is a child telling a story to a dying man) Should the synopsis be written in a straight format, or flow in the same manner as the book?
I'm just going to take a big fat guess here and theorize that your novel is not plot driven. You'll thus need to be as creative in your synopsis as you are with the novel. You may want to use short paragraphs for each major character and the journey they go on. You'll need a start point and an end point for the synopsis that covers the plot but it can come in the paragraphs about the characters.
A synopsis is a tool. You may need to run it through the forge to temper it for your specific task, but there's no rule against that. You DO need to preface the synopsis with an explanation of how you've altered the usual format or you're going to get people scratching their heads and thinking you don't have clue one.