ok. that worked very well:
<code>
    private static IWorkspaceConnection createNewWorkspace(ITeamRepository repo ,IWorkspaceConnection parentStreamConn, String workspaceName , String description , IProgressMonitor progressMonitor) throws TeamRepositoryException
    {
        IWorkspaceConnection newConnection = null;
        IWorkspaceManager wm = SCMPlatform.getWorkspaceManager(repo);
        IContributorHandle scopeHandle = repo.loggedInContributor() ;
        IWorkspaceConnection defaultFlow =  parentStreamConn;
        IWorkspaceConnection sourceWorkspace= parentStreamConn;
        newConnection = wm.createWorkspace(scopeHandle, workspaceName, description, defaultFlow, sourceWorkspace, progressMonitor);
        return newConnection;
    }

/**
     *
     * @param repo - An RTC reporistory object
     * @param searchName : a RTC workspace or stream name to search
     * @param searchKind : if you search for RTC workspace send: IWorkspaceSearchCriteria.WORKSPACES
     *  if you search for stream use:IWorkspaceSearchCriteria.STREAMS
     * @param monitor
     * @return - a connection object to the found stream/workspace
     * @throws TeamRepositoryException
     * @throws ItemNotFoundException
     */
    static IWorkspaceConnection getRepositoryWorkspace(ITeamRepository repo,String searchName , int searchKind, IProgressMonitor monitor)
            throws TeamRepositoryException, ItemNotFoundException {
       
        IWorkspaceConnection connection =  null;
       
       
        IWorkspaceManager wm = SCMPlatform.getWorkspaceManager(repo);
       
        int maxSize = 4;
        monitor.subTask("searching for desired workspace");
        IWorkspaceSearchCriteria criteria = IWorkspaceSearchCriteria.FACTORY.newInstance();
        criteria.setPartialName(searchName);
        //criteria.setExactName(searchName);
        criteria.setKind(searchKind);
        java.util.List<IWorkspaceHandle> workspaceList =  wm.findWorkspaces(criteria, maxSize, monitor);
        System.out.println("found " + workspaceList.size() + " matching workspaces for search pattern:"+searchName);
        if (workspaceList.size() == 1) {
            IWorkspaceHandle handle = workspaceList.get(0);
            connection = wm.getWorkspaceConnection(handle, monitor);
        } else if (workspaceList.size() > 1){
            System.out.println("search creteria was to common. serveral workspaces found:");
            StringBuffer buffer = new StringBuffer();
            for (IWorkspaceHandle handle :workspaceList ) {
                connection = wm.getWorkspaceConnection(handle, monitor);
                String desc = connection.getDescription();
                System.out.println("desc=" + desc  + " name="+connection.getName());
                buffer.append(" name=").append(connection.getName());
                if (desc != null) {
                    buffer.append(" description=").append(desc);
                    buffer.append('\n');
                } else {
                    buffer.append('\n');
                }
            }
            throw new TeamRepositoryException("workspace name is non-unique:"+buffer.toString());
        }

        return connection;
    }
</code>