\documentclass{scrartcl}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
\usepackage{colortbl}

\begin{document}

#+TBLNAME: Test
#+ORGTBL: SEND Test orgtbl-to-latex
|   |    A |    B |
|---+------+------|
| / |    6 |    2 |
| / |    4 |    9 |
|---+------+------|
| _ | suma | sumb |
|   |   10 |   11 |
#+TBLFM: $suma=vsum(@I..@II)::$sumb=vsum(@I..@II)

% BEGIN RECEIVE ORGTBL Test
\begin{tabular}{lrr}
 & A & B \\
\hline
/ & 6 & 2 \\ % see here
/ & 4 & 9 \\ % see here
\hline
$\backslash$$_$ & suma & sumb \\ % see here
 & 10 & 11 \\
\end{tabular}
% END RECEIVE ORGTBL Test

\end{document} 