In 2006, Rep. James Sensenbrenner Jr. suggested that the U.S. Chamber of Commerce consider registering as a Foreign Agent. Now, from an article entitled "Mexican lobby fights for truck program" (link):

The House has made it veto-proof clear: The controversial pilot program allowing big Mexican trucks to cross the U.S. border and travel into the country must end.

The Senate has yet to act, though. And Mexico and its U.S. big-business allies are ramping up their efforts to block the repeal, including a renewed warning by Mexican officials to retaliate against U.S. exports if the program is abolished.

Mexican Embassy officials say the year-old pilot program has been a positive development for both countries...

The U.S. Chamber of Commerce is bolstering Mexico’s efforts to save the program, arguing that the Mexican trucks are tightly regulated and offer unique business opportunities to the U.S. economy. And to highlight the issue, Chamber President Thomas Donohue recently traveled to Mexico to confer about the program with key officials.

"This whole issue is much more wrapped up in immigration and anti-Mexican sentiment that you see across the board," said Chamber lobbyist Janet Kavinoky, who leads the Americans for Transportation Mobility [fasterbettersafer.org]...

I'd like more information on to what extent the U.S. Chamber of Commerce is collaborating with the Mexican government.