AD9081-FMCA-EBZ VADJ

I'm using the AD9081-FMCA-EBZ with a Xilinx ZCU216 where i'm having to use a HiTechGlobal FMC extender/splitter so that the AD9081 board doesn't foul the QSFP cage on the ZCU216. It looks as if the ZCU216 can't determine what the VADJ voltage should be and I can't determine it from the documentation. Can someone tell me what this should be set to?