My baby who is almost 3 uses a belly band. (he has a very small bladder and it was damaged from him getting into green tea diet pills).
The bands are perfect...I use a regular baby diaper, do not unfold, and place sideways around the waist., I get a little larger belly band to go around his waist and the diaper. I found it to be the perfect solution. Most dogs won't have the urge to lift thier legs with the belly band on. Yorkies are already hard to train anyways, so if he is not broken by 8 months, he probably is too stubborn to do so. Don't give up...just give in and belly band him.