Re: Protel footprint
One way would be to create the pads by using fills. A fill will not automatically have solder mask removed in the PCB editor - true pads do. Once you have ceated the pad area with copper fills, create fills on the mask layer (which is a negative layer) to open only the areas needed for the device solder pads.
An alternate way would be to place true pads the size needed for the device, then use copper fill to expand the heat sink areas as shown in the drawing. The pads will be free of solder mask, but the fill areas will be covered with mask when the Gerbers are generated.