Adding button in screen 4050 in SAPMV45A

Hi all,

I added button in Screen 4050(SAPMV45A), Whenever User Clicks that button i need to display the screen 800(SAPMV45A). Also I should check the item level material number, If particular material number selected then for that number display should return vales. I need to add my Function code through VFBS or can i use standard Function code already available in T185* table.How can i call this screen? Will it display with vlaue or i need to do in anyother way?

Help me guys !

Thanks,