Inglês é melhor.
Mas é o que eu disse, veja:
Using a domain name
In case you want to use a different domain name for your supplemental shop rather than a subdomain/subfolder, you must configure your domain to point to the folder where PrestaShop is located. The URL rewriting is then done by PrestaShop itself.
Alternatively, you can create an alias for your domain name that redirects to absolute URL where your installation of PrestaShop is located. The way to achieve this depends on the control panel and options that your hosting company provides you with: "Alias" for Plesk, "Forward" for CPanel, "Aliasdomain" for ISPConfig, etc.
O sistema de multi-lojas funciona somente com sub-domínios ou sub-pastas do domínio master... outros domínios tem que apontar para a pasta.
Obrigado pela ajuda!