You won't need Reflections ON for specular highlights. Those are pretty much free as long as you have Specular Color, Size and Intensity set in the surface properties.
For more glass-like highlights, in your surface properties set "Specular Render Shader" to "Glossy" and in your render settings set "Plugin Shaders" ON. Then adjust the regualr specular properties to taste.
Make sure the transparency portion is truly set to zero, zero, zero.