Variables with dots in templates

I guess I stumbled on a problem I cannot solve by myself.

In my HTML template I have a form with check boxes like:

<input name="cb_src[]" type="checkbox" class="ricerca" id="cb_src[]"
value="utenti_servizi.tipo_abbonamento" {if
(isset($cb_src.utenti_servizi.tipo_abbonamento))}checked{/if}>

My problem is that $cb_src.utenti_servizi.tipo_abbonamento is never going to
be set because the real variable in php is
$cb_src['utenti_servizi.tipo_abbonamento']
I gues that having a dot in a key of an array makes a problem for Smarty
unless there's some other way to overcome the problem.

Is there anybody who can help me?

Valerio Santinelli