You can achieve this functionallity by adding a manual property set defintion to a property set that is attached to the objects that you are scheduling. Then you can just select the object and edit the property set definition value on the property palette. Then on your schedule you will need to add a column that references the property set definition created in the previous step. Just add the object(s) to your schedule and you should be finished. Just remember that you need to update the schedule information on the object and not the schedule itself.
