Generally, there's no way to add individual functions to the D* remote. However, there is a workaround. Just leave your TV in Full mode and use the the D* Format button to change aspect on the D* receiver. You'll cycle through 1080i/Crop, Native, LetterBox, etc., giving you the same result. If you get resolutions you don't want, like 480i, etc., just uncheck them in the HDTV settings on the D* receiver.
If you still want pix shape, you'll have to get a universal. One of the cheapest options is any of THESE
radio shack remotes. The 15-134 is most like the RC64. All are made by the same company that makes the D* remote. The code for your Sanyo on those remotes is probably 10154 and the corresponding advanced code for pix shape is 00106, which you can put on any button as follows: tap TV, then hold P for 2 blinks, press 994, tap P followed by 00106, press desired pix shape button - 2 blinks indicates success. Even if those codes don't work, you can learn all the buttons you need with the radio shacks or just about any other universals.
If there are any other options, Edmund will likely post them.