Another major shot fired in the Jesse James custody war -- this time, his ex-wife claims she can prove Sandra Bullock doesn't want to have a relationship with her daughter Sunny.
In court papers filed recently in Orange County, CA -- Janine Lindemulder insists that Jesse's "reasons" for wanting to move to Texas with Sunny are "wholly unjustified" ... and attacks Bullock to make her point.
Janine claims Jesse had argued that he wants to move to Texas "so his children could continue their relationship with Sandra Bullock" ... who now lives in Austin.
But in the docs, Janine points to the fact that Sandra had recently moved out of California ... and states, "Certainly if that relationship were that important to Sandra, she would have stayed in California -- where all of [Jesse's] children lived."
Janine -- who considers California her home -- wants the judge to rule that "[Jesse] not be allowed to move to Texas with Sunny."
Jesse and Janine are due back in court on Monday.