I'm going to order the genuine door step repair panel - http://www.minisport..._HMP441012.html
and later on in the project I will be replacing the flitch panels using this panel assembly - http://www.minisport..._ABD360200.html
However I'm unsure when I need to replace the a-post stiffener. My mini has been chopped about and I'm not sure what it is supposed to look like.
1. Is this a-post stiffener inc in the flitch panel assembly?
http://www.minisport.com/mini-spare-parts/info_08-01-278.html
2. Can the stiffener be replaced after the door step has been replaced given I'm replacing the flitch, or does it need to be replaced first?
3. Does the stifferer fit in as pictured below?

4. If so, how is this join between the stiffener and door step sealed / welded?

My drivers side stiffener looks to be missing after a bodge repair from a previous owner and the gap between the door step and flitch was filled with filler

But it is visible on my passengers side where the door step has rusted away ( spot a-panel hanging off, previously glued to flitch using a piece of angel iron)

Any help, advice or pics appreciated
Chris