Ship designer question (ship orientation)

Hi all,

I'm having a darnest time orienting a custom-built ship to fly right in fleet battles.  What determines where the front of the vessel is in ship builder?  I know it's related to how it shows up in the thumbnail preview (all ships face down-left), but I just can't get my ship to save in that orientation.  Figured the new "orientation grid" in the new version would help, but no luck.