I don't think you need worry. 11kg is about 25lbs and drawbar tensions are in the region of 2000lbs so the angle head is not likely to pull the drawbar down.
The spindle bearings at the bottom are a pair of angular contact back to back and preloaded. This bearing assembly can taken many pounds of upwards end load when pushing a large drill in so it will be able to take a similar end load down. It is not at all likely that 25lbs down is going to be anywhere near what they can take.