The University of Wisconsin - Milwaukee has moved to D2L version 10.
Updated help files are located at uwmltc.org
Even if you have already entered a grade, you can still change the item weight.
1) Go into "Grades"
2) Select "Manage Grades"
3) Select the grade item that you want to adjust the weight on
4) This will put you into "Edit Item"
5) In "Edit Item," under "Grading," you can adjust the weight given to the item. Then be sure to save.