function call in .htaccess ?

Hi,

I use something like this:

RewriteRule ^(.*).png$ ../../templates/png_help/$1.png

The links to png in my pages exist to this subdir, but in fact the png are
located somewhere else in a templates directory.
Now, I'm shuffeling folder layout, in part to support localisation etc.
therefore the location might differ based on variables.

Can I use external variables somehow in .htaccess ?
E.g. {TARGET_DIRECTORY}/templates/png_help/$1.png

Or call a function that outputs the directory ?
e.g. <?php echo DIR ?>/templates/png_help/$1.png

or .... ???

Your insights appreciated.