I'm looking through my style files and don't notice anything special to enable them. I'm currently using LEd with tex->ps then ps2pdf and I get them. So unless its one of these packages, it kind of just does it for me
Code:
\usepackage{graphicx}
\usepackage{epsfig}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{booktabs}
\usepackage{stmaryrd}
\usepackage{url}
\usepackage{longtable}
\usepackage[figuresright]{rotating}
\usepackage{mathrsfs}