Mint13 in VirtualBox, won't retain Arandr settings @ startup

[yenic]

I'm using Mint13 in a VirtualBox session, and when I set my dual monitor options correctly in Arandr, save them, set it to run on startup, it fails to initalize properly.

It appears that the primary monitor is not being detected properly when I set it to autostart the Arandr file, it's native resolution is 1920x1200 and when I try to load that file it sees the max as 1600x1200. Is there any way to get dual monitor working on startup?

I have a working dual monitor VM working in Ubuntu 12.04LTS so I thought this should be something I can accomplish. Maybe Cinnamon is better supported? I was hoping to be able to use Mint on Xfce.