As of Cognos BI 10.2 you can report of Salesforce direct without the need for Virtual View Manager:
http://www-01.ibm.com/support/docview.wss?uid=swg21614133&myns=swgimgmt&mynp=OCSSEP7J&mync=R
Blog of IBM Cognos TM1, Cognos BI, Cognos Express, CDM and other related stuff.