Smarty

I'm using Smarty to create a Blog engine.
The Blog's templates have a certain structure that must be kept.
e.g:

{%Blogger%}
{%BlogDateHeader%}
{%$BlogDateHeaderDate%}
{%/BlogDateHeader%} ...

I need to leave the unassigned variables intact in the template.
This means that if smarty doesn't recognize the element (variable not assigned or function does not exist) it would leave it in the te ...

I need this "unassigned sections" feature too, but unlike SiliconError I don't know ahead of time what blocks/vars should escape the smarty parsing.
What I need is for smarty to leave these blocks/ ...