[O] Defining new structural markup element

[Levy, Roger]

Hi,

I'm a relative org newbie and I expect that this question is answered somewhere 
in the manual, but I've searched and I can't find the answer.

I would like to define a new structural markup element for an org file and 
specify its translation into latex.  e.g., I'd like to be able to put in my 
document

#+begin_foo
bar
#+end_foo

and have this translated into LaTeX as something like 

\em
bar
\em

but I'd like to be able to flexibly specify the LaTeX commands inserted at the 
beginning and end of the "foo" block.  Is there an easy way to do this?

Best & many thanks in advance!

Roger