We apreciated your help and kindness regarding this matter.
Now we are sure that avast services sent us a mail with the instructions for renewal, the problem is that we have changed our e-mail and we didn´t get it.
We made also the mistake to send a mail to support@avast.com, in 17 Fev. 2006, asking instructions about renewal all the licences. Till now we did´'t get any response, but avast support services are right, this "problem" should have been sent to sales services and not to support (we are very green on this matters).
We sent today a mail to sales service to ask about the steps (link) to get the renewal of the expired licences.