How to bank/roll instanced nParticles?

[booboo_4ever]

hello all,

i am doing some work with flocking some flying creatures using nParticles in Maya 2011.

i am able to get the creatures to point in the direction they are flying using Velocity for Aim Direction.

but now i want the creatures to bank or roll when they turn as they move around. i tried checking on Compute Rotation and putting rotationPP into rotation of the instancer, but this does not seem to work (i keep finding tutorials recommennding to do this.)

is there an easy way to make the creatures bank / roll?

thanks for any help