I don't think Joomla template syntax will work outside of a Joomla template. We don't execute any sort of Joomla syntax replacement on our templates. The gantry won't work either unless you load in however $gantry is being defined.
I suggest looking into an extension called Mondules Anywhere and use its syntax in a delimiter field. It basically uses regex on the buffer, finds the matching replacement strings, replaces with a module. I've no experience with it, but many users report using it quite successfully.