PCI Certification

I received a call from an ASP.net e-commerce software provider and he emphasized that any e-commerce software used by a merchant needs to be PCI certified. He stated that his company's e-commerce software is PCI certified.

From their site it reads "July 2010 is the deadline for Phase 5 of the ' Payment Application Security Mandates*'. This VISA mandate states that 'Acquirers must ensure their merchants, VNPs and agents use only PA-DSS compliant applications'...Using a 3rd party payment system such as Google checkout or Paypal Express may be a solution but will result in decreased sales conversions."

If you do not store credit card information on a database, but only utilize a gateway/merchant such as Authorize.net (with all transactions SSL encripted), do the PHP software/dreamweaver extensions (eCart, Security Assist, etc) have to be PCI certified?

If so, are Webassist's products PCI certified?

If not, what PCI certification actions should a merchant using webassist products take?

Thank you in advance.

PCI certification is for when you are looking to store sensitive information like credit card information on your database. eCart utilizes payment gateways and all the payment gateways are PCI compliant. The code written by eCart is basically api calls to the payment gateways. This is my understanding of the PCI compliance issue.