You can not use the Salesforce Touch on platform edition? Why? The salesforce provides this functionality available? If yes, when?
Currently, Touch only works with Sales App. Since this app isn't available in the platform edition, I'd say that's why you can't use Touch. In the Spring 13 release, it looks like Touch will be able to be used with all apps so that makes me think you could Touch in platform edition too. Here's the link to the Spring 13 release notes: https://na12.salesforce.com/help/doc/en/salesforce_spring13_release_notes.pdf