Create a {if} statement in WHMCS

Im trying to create a specific IF statement on the clientareaproductdetails.tpl file in WHMCS - bottom line i'm trying to display some text on a page depending on the product the customer is looking at.

So this is what I tried (which does not work)

{if $id  == '17'} something {else} nothing {/if}

So if the product ID = 17 then display 'something' otherwise display 'nothing.

Any ideas if/how this is possible?

Thanks in advance.

H