The WebSphere Community Blog pointed out that there is a new WebSphere Application Server 7.0 Feature Pack available for download. This one will enable the Tuscany implementation of SCA inside the WebSphere Container.
It should be noted that this version of SCA is not the same one included in WebSphere Process Server. I would just assume that you can’t call a WPS 6.1 SCA Export from a WAS 7.0 SCA Import.