Using Chroma A615003 with 6160x

I am trying to use the Chroma 61604 in conjunction with a Chroma 615003 AC transformer to acheive 480Vac. I cannot figure out how to enable the A615003 programatically. The 61604 user manual only lists low, high ,and auto ranges. I need to enable 600V range, which I can do manually, on the 61604. When I manally go to 600V range, the A615003 is enabled automatically. Does anyone here have experience with this? 

Thanks!