Twilight director Catherine Hardwicke warns that Kellan Lutz and Ashley Greene could be replaced -- like Rachelle Lefevre -- in the hit vampire flicks if they ask for too much money to reprise their roles in Breaking Dawn.

"Ashley and Kellan have agents, managers, lawyers... you get all of these outside influences telling you you should hold out for this much because you're such an important part of the franchise," Hardwicke told UsMagazine.com at the Twilight convention in Vancouver on Sunday.

The Hollywood Reporter says Kristen Stewart, Taylor Lautner and Robert Pattinson have already received huge raises for their roles in Stephenie Meyer's fourth book, which is rumored to be split into two movies. But the secondary characters are still negotiating salaries.

A source tells Us that "Summit leaked the story to turn fans against the cast. They are leading the negotiations to the press and are trying to make them look greedy... Summit has made millions and the cast is just looking to get what they deserve."

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Said Hardwicke, "Possibly, Rachelle and Ashley and Kellan might not even be all that involved. They have all the other people telling them things and a lot of stuff can get mishandled, like what happened with Rachelle. There's so many possible misunderstandings. It breaks my heart."

"It could turn ugly. Do [these actors] deserve more money? Probably they do, on one level. But if everybody make so much money then... it's complicated. What a mess!" she continued.

The source tells Us, "The leads made 20 times as much on Eclipse than they did on Twilight," continues the source. "The non-leads are not asking for anything close to that."

Meanwhile, Pattinson and Stewart tell USA Today why they haven't been photographed together recently. (Us Weekly reported last month that they have a system for sneaking around to see each other. While filming Eclipse, out June 30, they spent most of their nights together, but, says a source, "always had two separate drivers to give the illusion they weren't an item.")

"We have gotten better at hiding over the last year," Pattinson admits. Agrees Stewart, "We are just good hiders now."