SageTeX in export

[mailinglists@nawaz.org]

Hi,

Some background for the interested:

Sage (http://www.sagemath.org/) is a free open source mathematics
system. It essentially takes a number of well known open source math
packages (Pari/GP, Maxima, etc) and provides it all to you under one
interface, all glued together with Python. 

I highly recommend it. There was even a post here a few days ago
regarding including Sage into Org-Babel.

I want to talk about SageTeX. It's a package that allows you to call
Sage code from within your LaTeX document. You insert a Sage command
(e.g. plotting some data) and it returns the result - either an image or
relevant LaTeX code. Kind of like literate programming.

Here's how it works. If your document is file.tex and it uses the
SageTeX package, you run pdflatex on the .tex file. This will then
produce a sage script called "file.sagetex.sage". You then manually run
this sage script using Sage. Then you run pdflatex again and it will
include the results from your sage script into the document.

I'm finding myself embedding Sage code into a document I'm writing which
is meant for a LaTeX export. My problem is that Org mode's LaTeX export
can't handle the steps in my previous paragraph. I'm sure it's trivial
to do via some hook, but I'm no good at Elisp.

All I need is a way for the export to:

1. After running pdflatex, check if there is a file called
   "<org_file_name>.sagetex.sage".
2. If it's present, run sage on it, and then rerun pdflatex.
3. If it's not, nothing more is left to do.

I'd really appreciate if someone could tell me how to enable this with
Org mode's export.

Thanks!