Need help with printing a part on the Davinci Jr

I am trying to print the 80% pokeball top part from Thingiverse but I cannot get the part sliced with supports in any useable manner.  Because of the hinge on this file I there is a gap between the build table and the rim of the dome. Only the hinge is touching the build platform. I printed the larger version upside down (it looked like a bowl in this orientation) but the top of the dome was all messed up after removing it from the buildplate. I cannot find anyway to add supports so it only supports the rim of the file and doesn't add any supports in the center of the dome. XYZware wants to add supports at the rim and in the middle of the dome but it doesn't print right for some reason when it does this.

How can I get supports in an STL format only around the rim of the dome so that I can run the file through xyzware then print it easier? I have also tried meshmixer and it completely failed with the weird supports that that program generates.

I've attached the STL incase it helps.