Inventor corner relief question

[dm020]

Hi,

I'm having a small problem trying to replicate a type of corner relief we currently use on our sheetmetal products, which are manufactured from AutoCAD drawings.

Attached is an example I created in Inventor by drawing the flat pattern, extruding and folding.






However what I would like to know is how to create this using the flange and corner seam functions.
I can already make the 45 degree relief cut using corner seam, it is simply getting the corner relief such a shape that it resembles the 3D and flat pattern examples.

Any help would be much appreciated.

Thanks,

Dean