To be "behind" the lawsuit, Canpire must have some form of ownership over the works. The court materials show that Voltage claims ownership. So Voltage is and remains "behind" the lawsuit. Canpire are Voltage's "experts" on the issue of who is infringing. Barry Logan of Canpire has provided an affidavit in support of Voltage's motion for disclosure. The affidavit is inside the motion materials, available at http://cas-ncr-nter03.cas-satj.gc.ca/IndexingQueries/infp_RE_info_e.php?court_no=T-2058-12. So Canpire's role has not been a secret. As "experts," they might hope their side wins (although 'experts' in Canadian law should not be advocates) and they get paid handsomely, etc. but that in itself is not being "behind" a lawsuit.
What is secret at this point is whether there is some form of agreement between Voltage, Canpire, and Voltage's lawyers (Brauti Thorning Zibarras) with respect to the monies they presumably will get from the mass collection letters and whether the agreement violates the any laws on champerty or maintenance or perhaps, as in the UK case (ACS:Law), lawyers' codes of conduct.
In the Voltage case, CIPPC (Samuelson-Glushko Canadian Internet Policy and Public Interest Clinic www.cippic.ca) was granted an intervenor status (http://www.cippic.ca/en/node/129298) and was allowed to produce its own materials and experts (which it did) and examine Barry Logan (Canpire's principal) on his materials (which I am not sure has been done yet).
The interesting question is how Logan will be cross-examined on his affidavit.