Perhaps the thorniest ethical issue when it comes to third-party litigation financing is who controls the case, the client or the financier?

Burford Group, one of the largest litigation financing funds in the world, states unequivocally on its website that Burford is not allowed to manage litigation. “We also don’t get any rights to control the settlement of the litigation,” Burford says on its website. “That is something that remains wholly in the litigant’s control.”

An exhibit filed by Chevron Corporation’s lawyers at Gibson, Dunn & Crutcher on Tuesday in its civil RICO case against plaintiffs lawyer Steven Donziger and others raises questions about those statements. Buried within the documents is a confidential presentation given by Burford in June 2010 outlining proposed economic terms for its funding of the Ecuadorean plaintiffs litigation accusing the oil giant of pollution, and it suggests that Burford pressured the plaintiffs not to settle too low. (Skip to Exhibit 2405).

According to the presentation, Burford was concerned about an “unnaturally low” settlement. To prevent that, it apparently asked that the plaintiffs not to settle for less than $900 million without Burford’s consent. In the alternative, if the plaintiffs settled without Burford’s consent, then Burford wanted to be compensated as though the settlement were $900 million. “Because control of when, and for how much, to settle this case is not in Burford’s control, Burford needs to be protected against an unsatisfactorily low result–which hopefully will never be relevant here,” the presentation stated. The document also proposed a 1 percent recovery for the first $2.5 million invested and a further 1 percent for each subsequent $2.75 million, up to a maximum investment of $15 million.

The presentation pre-dated the formal agreement signed on October 31, 2010, between Burford and the law firms representing the Ecuadorean plaintiffs: Patton Boggs, Donziger and Associates and Emery, Celli, Brinckerhoff & Abady. In the agreement, Burford, through its subsidiary, Treca Financial Solutions, actually negotiated a seemingly better deal. According to the agreement, if the plaintiffs agreed to a settlement below $1 billion, then Burford would be compensated as if the amount were $1 billion. Additionally, Burford would receive 5.545 percent of any recovery provided it invested the full $15 million. (Fortune‘s Roger Parloff described the terms of the actual deal in this article last year.) Burford ended up only investing $4 million and sold its stake in the case while retaining an unspecified interest in the recovery.

The plaintiffs won an $18.2 billion verdict in Ecuador in February 2011, but U.S. District Judge Lewis Kaplan issued a preliminary injunction one month later barring enforcement of that judgment. The Second Circuit vacated the injunction, and the plaintiffs are attempting to enforce the judgment in Canada and Brazil. Kaplan issued another ruling on Tuesday concerning enforcement of the judgment that was a mixed result for both sides. Our affiliate New York Law Journal has coverage of that ruling here.

Chevron spokesperson Kent Robertson called the filing “highly revealing.” Said Robertson: “It’s been very clear for some time that the lawsuit in Ecuador has nothing to do with the Amazon and has everything to do with a return on investment. That’s evident from the outtakes from the movie ‘Crude,’ from the plaintiffs lawyers’ internal correspondence that we have through discovery, and in Burford’s funding agreement.”

Burford, for its part, dismissed this document as irrelevant. “As previously disclosed, Burford has had no capital at risk in the Chevron matter for more than 18 months now. The document in question was filed as exhibit 2405 as part of a discovery dispute between Chevron and Patton Boggs having nothing to do with Burford. In any event, the contents of this marketing document–which long predated Burford’s short-lived investment–are nothing new in this ongoing matter,” said Burford chief executive officer Christopher Bogart in an email statement.

Chevron’s attorney, Gibson Dunn partner Randy Mastro, was unavailable for comment. Patton Boggs partner James Tyrell did not respond to a request for comment.