Problem margins Xerox 7530 + Fiery

I use a Xerox 7530 with a Firey RIP and Command Workstation. The problem I have is with the margins with SRA3. I want to use as much of the paper as possible and when I use A3 I have about 4mm margin that can't be printed which is fine. But when I use SRA3 I have 4mm on the short side but almost 8mm on the long sides. See included screenshots from command workstation.

Any ideas? The unprintable 8mm cuts off my cutmarks sometimes and becomes a real pain...