3D -> 2D

Hi! 1) I have point in 3D. I need to know that, this point will be rendered on the front surface, and if - then, what co-ordinations it will have (2D position on this surface). I was trying with PR_Globals.PR_ViewMatrix and PR_Globals.PR_ProjectionMatrix, but - no result I need it to render sun in my scene. I don''t want to testing collision between faces, and sun''s ray - just at the start of my scene, I want to put point on surface (specyfic color), then render my scene, and at the end - check color of this point. If it''s ok, then I will render lens flare. 2) Next question. I have an entity created as sprite. How can I rotate it (Z axis). Please, help... Best regards, Tomasz Przechodzki