Biblatex - style = alphabetic - change plus sign

I use biblatex with Biber and alphabetic style. In the case your citation has more than three authors this style will put a plus sign (+) in the label. I try to get this plus sign into superscript. Does anyone know how to accomplish this?

Just in case you might not exactly know what the alphabetic style looks like. For entries with two or three authors it will take the first letter of each authors' surname and put the last two digits of the year behind them. If there are more than three authors the label will carry the first letters of the surnames of the first three authors (EDIT BY LOCKSTEP: only if you set minalphanames=3, hereby overriding its default value of 1), put a + for the remaining one and put the last two digits of the year at the end. An example looks like this:

• A. ASurname, B. BSurname, C. CSurname (2003): Title.

--> [ABC03]

• A. ASurname, B. BSurname, C. CSurname, D. DSurname (2004): Title.

--> [ABC+04]

Redefine \labelalphaothers.

\documentclass{article}

\usepackage[style=alphabetic,minalphanames=3]{biblatex}

\renewcommand*{\labelalphaothers}{\textsuperscript{+}}

\usepackage{filecontents}

\begin{filecontents}{\jobname.bib}
@misc{A01,
author = {Author, A. and Buthor, B. and Cuthor, C. and Duthor, D.},
year = {2001},
title = {Alpha},
}
\end{filecontents}