% A callout hanging off a node, not a band, must dirty the build.
\documentclass[border=2pt]{standalone}
\usepackage[en]{superfig}
\sfsetrole{x}{sfTeal}
\begin{document}\begin{tikzpicture}
\sfrow{R1}{10mm}
  \sfnode[role=x]{A}{A}{12mm}{8mm}
\sfrowend
\sfcallout{N}{3cm}{A}{aside}{anchored to a node}
\end{tikzpicture}\end{document}