The development of collaborative service ecosystem relies mostly on software services spanning multiple organisations in order to provide agile support for business applications. By moving part of their information system on Cloud infrastructure, companies take advantage of new Business models and scalable environments, increasing IT productivity while reducing IS management costs. Nevertheless, this underlying outsourcing strategy may be braked by a lack of security and trust on this new infrastructure model as traditional security engineering and deployment methods are not designed for such an agile and opened environment. To overcome this limit, we propose a multi-dimensional model integrating both the cloud level (XaaS) and the cloud characteristics (Private, public, hybrid) to generate convenient security policy in a dynamic way. Based on security patterns, our multi-dimensional solution has been implemented to capture security requirements related to both information system design and runtime environment.