Special characters in S type colum from siunitx package

Question

I'm doing a table with a S column type from siunitx package (I've recently started to use this package). I usually represented empty values in cells using the character ---, however, S type colum doesn't alingn correctly this symbol. Hoy can I put this symbol in the center of the column?

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{booktabs}
\usepackage{siunitx}
\begin{document}
\begin{table}[htb]
\centering
\caption{Example Table}
\begin{tabular}{cS[table-format=2.3]}
\midrule
\textbf{Parameter} & \textbf{Value}\\
\midrule
Parameter 1 & 12.56\\
Parameter 2 & 9.038\\
Parameter 3 & 12.6\\
Parameter 4 & 0.732\\
Parameter 5 & \text{---}\\
\midrule
\end{tabular}
\end{table}
\end{document}