Using ShowDataFormUIAction in the UI Model

I want to use the ShowDataFormUIAction to open a data form in vb code using the UI Model. I have not been able to find good documentation about this. Does anyone have any examples so that I know even how to begin? Or any idea where I could find documentation about the process? What I want to do is open the Merge Two Constituents form with the source and target fields filled in from selections in a different form.