Introducing New Kitten to Resident Older Cat?

I have an issue with introducing a new kitten to my resident cat. The resident cat is 13 years old and has always been solitary and generally doesn't like other cats. In the past, she has tolerated 2 other cats and they were both males and younger cats (they were neighbors' cats). We recently got a new 4-month old kitten from the pound (male) and he is very friendly and can be quite playful at times. For most of the time, he is confined to a bedroom with his own toys, litter, and food bowls. My resident cat has the rest of the house with her own stuff, too. They're not sharing anything at the moment. They have met a few times in the main areas of the house under our supervision, for a short period of time (i.e. one hour or so).

On occasions where my resident cat meets him, she will hiss at him. The first time they met, they both touched noses and she hissed first, and then he hissed back at her. We separated them immediately. She continued to hiss at him whenever she sees him, but since then he seems to not show any signs of retreating. He would just go about what he is doing and ignores her (he wouldn't go near her, though). I think she's annoyed at this and that's why she continues hissing. Last night they were both out in the main areas for longer and she retreated and hissed at him continuously. She was visibly upset, and when we put him back in his room, she was still upset at us and she continued hissing and complaining to us for another hour or so.

What should I do so that the new kitten understands that she wants to establish dominance? And will my resident cat eventually get used to him?

Thank you.