You have to create 'Value Help' for that. Just right click on the input form & go to the controls of that variable. Below properties there is option for 'Add Value Help'. By creating valule help you will get one 'Push Button' next to this variable. When you click on this one pop up will get opened & you will get all master data values for that field. You can select from there. Please refer the link below -
Just try this, I think this is what you are looking for.
Edited by: Sandeep Patki on Jun 4, 2009 8:46 AM