AUTOPIPE VESSEL - NOZZLE DESIGN- WELD SIZE

In AutoPIPE Vessel nozzle design tab, how to edit the leg size of the weld on the outer side of the reinforcement pad(i.e. Weld Size-Outer nozzle weld)?

The option, Weld Size-Outer nozzle weld, meant to enter this value is never editable. 

Request your help in this regards.