Paneling and Trim - Trim Around Newel Post

I recently replaced the newel post, railings, and spindles on my staircase. Left and right, front and back in the following description are as if you are standing in front of the staircase getting ready to climb it. The new newel post is smaller than the old one, thus there is a gap of approx ¼” on both left and right side of the newel post between it and the stair tread. The post is cut into the tread so that it’s front face is flush with the front of the tread, which is a rounded bullnose. The back of the newel post is flush with the tread. In retrospect I should have replaced the tread, but here I am.

The dilemma is how to trim it. I can put trim along the right and left side of the newel, but then there is the gap on left and right side you can see viewing the newel and tread from face on. I think this is too difficult to fill and colour to match. Also ending any trim at the front of the bullnose has me puzzled how to get a smooth transition.. The ideal would be some miraculous flexible trim that wraps down around the face of the bullnose.

Any ideas? Thanks.

Could you post a couple of pix on a site such as photobucket.com and copy/paste the IMG code in your reply post? That way we could see what you see. Usually there is sufficient space between the newel post and the bullnose for small trim, but your case may be different. It would help for us to see it.