Flexy dynamic includes

Hi, I've just started using flexy and I'm trying to do something like the following: I have a template that I want to use throughout my site that has the standard header, footer, etc.. From this I would like to include various page-specific templates. So the base template would be: <html> <h1>My Site</h1> <h2>Page title</h2> <flexy:include src="{incfile}"> </html> Then I would set the incfile variable to specific-template.html or whatever. However when I try that, I get the error: Flexy:Include without a src=filename The incfile variable is definitely being set correctly, but I'm guessing it doesn't get substituted before the include is parsed. Does anyone know if this is possible, but I'm doing it wrong - or if there's a better way to achieve what I'm trying to do? Thanks in advance, Paul