Congratulations on coming out to your dad. Sounds like it went well!
Did you tell him you want to be referred to with male pronouns? If you didn't, he probably just doesn't know that you would like that. Transsexuality is probably new to him, and you can't expect him to know what you'd like without telling him.
Right now, he's only known for two weeks, you got to give him time to let the information settle. You've always been his daughter in his mind, and it will take a lot of time before he can think of you as a son. Not saying this to be mean, but to get you to realise his mindset.
I came out to my parents just over a month ago. Whenever I call my dad, as soon as he realises it's me he says "Hi girl!"
Why? Because he's done that his entire life. And because I haven't told him I would prefer male pronouns. So I don't take offense, because I know he doesn't do it because he doesn't believe my regarding my transsexualism.
Just some stuff to think about.
Take care,
Vincent