Using Two Lego NXT in a single Project

Hi all, I have a problem to get Two nxt up in a single project file....

What I have done is following the LegoMotorSamle:


And I success to control the 3 motor...

By following the step... I create a new manifest file which consist of 6 motor and 2 bricks

3 motor connect to the COM40 brick and 3 motor connect to the COM41 brick...

Then I extend the partner list like this:

***********
************* motor:MotorA40
***********
***********
************* motor:MotorB40
***********
***********
************* motor:MotorC40
*********** ***************
***********
***********
***********
************* motor:MotorA41
***********
***********
************* motor:MotorB41
***********
***********
************* motor:MotorC41
***********




In the Project side... I link it up like this :
*[Partner(motor.Contract.Identifier + ":MotorA40",
*********** Contract = legomotor.Contract.Identifier,
*********** Optional = false,
*********** CreationPolicy = PartnerCreationPolicy.UsePartnerListEntry)]
******* private motor.MotorOperations _motorA40 = new motor.MotorOperations();


******* [Partner(motor.Contract.Identifier + ":MotorB40",
*********** Contract = legomotor.Contract.Identifier,
*********** Optional = false,
*********** CreationPolicy = PartnerCreationPolicy.UsePartnerListEntry)]
******* private motor.MotorOperations _motorB40 = new motor.MotorOperations();


******* [Partner(motor.Contract.Identifier + ":MotorC40",
*********** Contract = legomotor.Contract.Identifier,
*********** Optional = false,
*********** CreationPolicy = PartnerCreationPolicy.UsePartnerListEntry)]
******* private motor.MotorOperations _motorC40 = new motor.MotorOperations();

******* [Partner(motor.Contract.Identifier + ":MotorA41",
********* Contract = legomotor.Contract.Identifier,
********* Optional = false,
********* CreationPolicy = PartnerCreationPolicy.UsePartnerListEntry)]
******* private motor.MotorOperations _motorA41 = new motor.MotorOperations();


******* [Partner(motor.Contract.Identifier + ":MotorB41",
*********** Contract = legomotor.Contract.Identifier,
*********** Optional = false,
*********** CreationPolicy = PartnerCreationPolicy.UsePartnerListEntry)]
******* private motor.MotorOperations _motorB41 = new motor.MotorOperations();


******* [Partner(motor.Contract.Identifier + ":MotorC41",
*********** Contract = legomotor.Contract.Identifier,
*********** Optional = false,
*********** CreationPolicy = PartnerCreationPolicy.UsePartnerListEntry)]
******* private motor.MotorOperations _motorC41 = new motor.MotorOperations();

It is just similar to the sample...* But the problem is, when I try something like:
*************************** _motorA40.SetMotorPower(new motor.SetMotorPowerRequest(1.0));
*************************** _motorB41.SetMotorPower(new motor.SetMotorPowerRequest(1.0));

so that COM40's MotorA and COM41's MotorB should be at power 1...
But the result is only COM40's Motor A and Motor B will rotate...
That is... the _motorB41 still pointing to the COM40's motor.....

I have due with this problem quite a few day already.... can someone tell me what wrong is it? Thanks~