Excited urination and submissive urination are two very different problems.
When you ignore him, are you avoiding all eye contact and speech? My advice is to keep doing this - for at least 5-10 minutes or until you notice that he is losing his interest in you - then put the leash on and take him out (again without saying anything to him). Then praise him lavishly after he pees outside.
We've been battling the same thing with our young doxie; she'll be a year old in July and she is *almost* over her excited piddles.