Stock widget in Apex Launcher How do I get to use stock widgets (like email) on HTC Sensation 4G running on ICS and Sense 3.6 with Apex Launcher Pro?
These widgets are not standard widgets. They use non-standard APIs of the Sense launcher and thus that other launcher's don't have and thus, they can't use them.

This is why, you can't use Sense widgets with custom launcher.