Bad aim with potty pads

Question
I have a three year-old male chihuahua named Little Paw.  When we first got him, we trained him to pee on potty pads.  He always went on the side of the pad, with some on the pad and some on the carpet.  We quickly made him an indoor/outdoor dog and he's been very happy using our cat door to come and go as he pleases.  Due to him escaping from our yard the last few months, we now have him inside only with only supervised visits to the great outdoors.  I take him outside for potty breaks frequently and often times he does not go during those times.  I have potty pads out and he does make an effort to use them.  He just misses the point of getting all the pee on the pad.  I tried taping a pad partly up the wall and he did go on just the pad.  That only happened once though.  I have not been able to reproduce those results, lol.  Do you have any ideas how to teach him to aim for the middle of the pad?  I thought about making a target for him.  Maybe a little fire hydrant?  The pads I use have blue sides and I wondered if he might be aiming for the darker color.  I also tried putting to potty pads overlapping each other and that didn't work either. Any ideas would be so greatly appreciated.
Thanks,
Jenny

Answer
Maybe your fire hydrant would work, or something big enough to give him a target.  Maybe a jar with a lid and sand in the bottom to keep it upright.  

Note, if he is not neutered, doing so might make it easier to keep him in the yard.  He would have less incentive to play Houdini whenever a female upwind came in season.  it also reduces the chances of cancer in later life.