Modal Form and Parent Form

HI,

I created Form(using Screen Painter),which i can access from Edit Text i created in PO Screen using TAB key event. i made my form as Modal Form.i used the concepts given in samples.

when multiples screen are in open status while triggering my Modal form its working and always on top.but i want my parent form(MY PO) always behind my Modal.then only i can able to load data from my modal form to parent PO without any problem.how can i acheive this.

Regards,

Ganesh K