Using jqtransform plugin on all but one form

Using jqtransform plugin on all but one form

We're using the jQuery jqtransform plugin to style our site's forms.
There's one form though that we don't want it to change. I modified the
script that runs jqtransform on all forms to the following:
$('form:not(.classOfFormWeDon'tWantToChange)').jqTransform();
It still has the same effect as running it on all forms though. Is
something wrong with the way the :not selector is being used? Thanks