Do you know of really good products which say to your dog, "Poop Here"! ?

  Pooping Problem I have two small dogs, Charlie and Mookie, and live in a 2 story condo and have a small yard, so I have a doggy door. Charlie particularly randomly poops inside.  Not always, just sometimes.  We feed them at a specific time in AM and PM and put  food away after about 45 minutes.  We have been taking them for walks about a half hour after eating hoping to get them to poop on the walk.  Mookie almost always poops on the walk.  We have a word we say for pooping and a treat to whoever actually poops. We live in Oregon where it gets rainy and cold in the winter.  We would like them to both go out the doggy door on their own and poop.  When we go out to the backyard with them hoping they will poop after their meals, we sometimes stand there for a half hour and still nothing happens.  The dogs lie down and sometimes go to sleep even though we say the "word" occassionally to remind them as to why they are there.... Because of lack of interest in the back yard, we started the walks which seem to work 90% of the time for Mookie, and 50% of the time for Charlie. I can tell the difference between their poop.  Mookie has only gone inside the house once in the last 2 months.  Charlie has gone about 6 times in the same amount of time. I have a spray that is suppose to say "Poop Here", but it doesn't seem to work.... Do you know of  a product that has had good reviews from actual users?