Door pillar and bracket - how are they joined?

As per the title. I have quite a bit of rust around the chassis to bulkhead bracket and have bought a new one. Can't see how it's joined to the pillar - welded, or just slots inside?

I take it that this is an outrigger?

These are welded to the chassis and bolted to the bulkhead.

No - I mean the bit that bolts onto the outrigger. They are available separately. From looking at the parts manual, they appear to be part of the bulkhead as they are supplied. Looking at the bottom of the bulkhead/door pillar leg, I can see they are a seperate construction from the door pillar, made from thicker steel. But I can't see any welds holding them to the door pillar. The bolts that hold the bottom door hinge on also pass through the upper part of this bracket. Just wonder if anyone here has changed them before?