Check a raw value in template

[pjdaley]

I am trying to use this in my template:

<vb:if condition="{vb:raw isvalid} == 1">
      some html code here
      </vb:if>

However this seems to give me

The following error occurred when attempting to evaluate this template:
%1$s
This  is likely caused by a malformed conditional statement. It is highly  recommended that you fix this error before continuing, but you may  continue as-is if you wish.

--------------- Added [DATE]1271882047[/DATE] at [TIME]1271882047[/TIME] ---------------

I ended up just doing this check via the PHP however, I would still like to know if there is a way to do this...