Has anybody found a method to get Server Side Includes to operate in the Magento description of product?
I attempted adding one and also the released page didn't show this content I am attempting to include.
For instance, I added this towards the description of product area within the Magento Admin:
<!--#include virtual="../test.php" -->
You are not likely to have the ability to do this.
Magento product explanations are saved within the database, after which PHP brings them out and shows them
Server side includes are processed before Apache ever worries about outputing any content.
Magento does not possess a feature that's much like SSI. You can most likely write an override towards the Product class in Magento to acheive this effect, but it might be non-trival and past the scope of the simple StackOverflow answer.
Best of luck.