Utilising new WHMCS templates within the integration plugin

When using the WHMCS WP Integration plugin you are asked which template to use, the options are 'auto detect, six and portal'.

I do not want to use any of these, in fact I would like to use either a self designed theme or a purchased one such as 'flat - http://whmcsdesigns.com/'.

Is there a way I can make this a possible selection? Or is integration only possible for the standard templates?