I haven't done much with Design Studio, but if it allows you to send HTTP Get requests and consume HTTP Post requests, you can use REST.
For more information about how to use REST, see the RESTful Web Services help docs, which you can find here: SAP BusinessObjects Business Intelligence platform 4.1 – SAP Help Portal Page. Also, there are some samples for how to code for the RESTful Web Services that you can find in the RESTful Web Services space on SCN here: http://scn.sap.com/community/restful-sdk.
-Dell