The frame-packed 3d format is getting played without any issue.
When i contacted benq customer care, they said particular this model (W1080ST) is having problem with 3d content when it is from hard disk. Because of this, signal from bluray through HDMI is not identified as 3d and hence the 3D option in projector is disable.
They indicated that there might be firmware upgrade required for this capability.
In other forums, i got to know that there was firmware upgrade for W1070 (i.e. 1.06) which has capability to play SBS/OU 3D format. May be either this upgrade is also applicable for W1080ST model.
Trying to check with BenQ customer care so that they can confirm if there is firmware upgrade for this model.
Will keep this forum posted.