Not sure how this could be added as a package to Sentastico. It is not a stand alone script. You need to use their website to create and then publish it on your hosting space. Through initial checking, there is nothing that can be deployed in a client's hosting space that integrates it with Silex. If you can find out what files/folders are needed to be placed on the client's hosting space I could check it out more.
Although, ImpressPages is already available through Sentastico which is a drag-n-drop site builder and is installed directly to the user's hosting space without going through a 3rd party web site to create them.
Although, ImpressPages is already available through Sentastico which is a drag-n-drop site builder and is installed directly to the user's hosting space without going through a 3rd party web site to create them.