If you can only enter one of the entries (either 104 or 107) in the drop down box, just enter the box 104 amount in one T5013 slip entry and then select "add another T5013" and enter the same identifying tax information for the parnership in the second T5013 slip and select the drop down box in the second slip and enter the box 107 amount in the second T5013.  This will ensure both amounts are correctly transferred to the tax return.