Hmmmmm inside joke with my girlfriend huh?
You might try this. Get a bleach bottle (something heavy that cannot tip over) and cover it with a pee pad (use duct tape - you guys are great with that stuff) and then place it on the pee pad. I have not tried this but they do have a product at Petsmart that makes little ones want to pee on things and maybe if he is like all the other little boys out there he will want to lift his leg on it. Once his smell is on this maybe it will encourage him to use the peeing bottle on the pee pad. You could try this outside and then start bringing it in and placing it on the pad.
Now having said all this, I do think it sends crazy signals when you are trying to do two different things and you are soooooo lucky that he is housebroken but I understand why you would like for him to be comfortable during the day.
Hope this helps.