[O] inline src_R also in latex src block

[Michael Bach]

Hello,

I am using org-mode version 7.8.02

I can successfully do inline `src_R' e.g. via

--8<---------------cut here---------------start------------->8---
\begin{equation}
  src_R{4 + 4}
\end{equation}
--8<---------------cut here---------------end--------------->8---

where `8' is put into the equation environment on export.  Sadly, there
is no LaTeX font lock in the org file this way.  But when I do it inside
a latex src block providing font lock, e.g.

--8<---------------cut here---------------start------------->8---
#+name: test
#+begin_src latex
  \begin{equation}
    src_R{4 + 4}
  \end{equation}
#+end_src
--8<---------------cut here---------------end--------------->8---

the `src_R' is put in literally on latex export.

Is there a way of preprocessing this latex src block with babel for R
prior to exporting?

Thanks in advance,
Michael