Above solution worked great (re-posting solution from above since I don't have enough reputation to add comments and confirm solution). Now my sublime shows highlighted searches clearly, and additionally I can see the highlights on the mini-map (or maybe I never noticed minimap before, but at least it works well now).

I just added above code into the user defined settings ("Preferences" -> "Settings - Syntax Specific").

"name": "My colour scheme",
"globals":
{
    "background":     "rgb(0, 0, 0)",
    "foreground":     "#aaaaaa",
    "caret":          "red",
    "line_highlight": "#222222"
},