extendscript or c++ :How to get and set transitions' components or properties in premiere pro?

How to get and set transitions' components or properties in premiere pro?Recently i am developing a c++ transition plugin：coolmation, i use cep to use it:

var effectToAdd = qe.project.getVideoTransitionByName(“coolmation”);

it works!But i have to set some values in this plugin!Is there anyway to make this?I can easily get or set values in effects,but  transitions seems difficult!No matter get value in cep and set value to plugin,or directly get values in c++ plugin ，how can i make it？Could you give me some advice；

In real practice，i need to get clips’ position value，then set to c++  transition plugin~ if c++ has

 api to get value is best!