I'd talk to him, as he sounds like a good man who would try to understand where you are coming from. However, it may take time to get to the point you want, and he may take longer than you do with his daughter.
I'm a stepmom. My DSD is 20 now, but I've known her all her life and been her stepmom for 12 years. I love her and think the world of her. However, I admit it took a few years for me to completely warm up to her and feel as comfortable around her as I do now.
I always treated her kindly, showed her love, did everything for her I possibly could, and she was a wonderful, kind child who was very easy to love, but in looking back, I wasn't as relaxed or open with her as I am now, and I certainly wasn't as physically demonstrative as I could have been. DH greatly encouraged me, and that helped, but honestly it just took time for me to feel at ease with her and it wasn't something that could be forced.
For example, with my nieces, I hugged and kissed them without a second thought, but with my DSD, I hesitated and honestly felt a little awkward--sometimes even wondering did she really want me to hug her, whereas with my nieces, I knew they loved their aunt.
It wasn't that I didn't care about her, but it just didn't come as naturally to me. That changed over time, but I think we needed that time to really get to know each other and gel together. That may be the situation here as well. As long as he treats your daughter with love and respect and care, I would give it some time.