I think there may be something to put in their food, although I am not sure of that one. You can take the dog out yourself and train it to go in one spot, so the burned grass isn't everywhere.
Or you could try a pee post, it's put into the ground and the scent of it (supposedly) makes the pup want to pee on/near it.
http://www.petco.com/product_info.a...ggle=1&ei=UTF-8