How do I add new (stange) keywords to FileTypes

I'm trying to convince my IDEA to edit LaTeX files; but the keywords in LaTeX are very different form the keywords I normaly use in IDEA.

The keywords in LaTeX start with a \, such as
\begin{...}
\twocolumn
And so on.

I cannot get IDEA to recognize "\begin" nor "
begin".

Any suggestions?

- Jake