Freddy,
You could use SythMaster with Studio One 3, as long as you were either using Studio One 3 Professional or Studio One 3 Artist + the AU/ReWire AddOn.
Unfortunately, you are using the FREE Version called Studio One 3 PRIME; which does not support the usage of 3rd party plugins.
Here is a link to the Feature Version Chart:
http://www.presonus.com/products/Studio-One/compare-versions