Propagating a miter flange across a closed corner?

I am trying to model a panel and am having trouble getting itto work. I'll attach jpegs for reference.

The first one called miter edges.jpg, shows the edges i wish tohave the mitered flange propagate about; they are highlighted inblue. SolidWorks will not give me an option to propagate the miter,and it tells me that the two edges i wish to propagate to areunusable.

The second image shows the detailed profile of the miter flange,notice this will create two 45 degree meetings which are parallelto the only rendered sheet.

Am I going about this the wrong way or missing something?

I also tried creating edges flanges for all 3, closing the corners,and then adding miter flanges for just the tops of the flange, thatdidn't work either.

Help!

SolidworksSheet Metal