I am stuck at 90% modeling AUDI TT please help

[cano-scotland]

The car looks nice so far i think but I am stuck with the mirror.
I do not know what to do to get squared corners in the opening for the transparent plastic with the leds.
Wherever I place edge loops it looks blotchy and crappy. Or if I do not put any extra edges then the corners get rounded like in the first picture.
Any idea to fix that?

Thanks

This is the mirror I want to model:

This is what I got so far:

THis is the mirror with rounded corners in the opening that I do not like:

If I try adding edges like this:

Then this is what happen:

Or if I try this:

This is the smoth version that is not good:

I tried lot of alternatives but having more or less same crap result, what to do?
Please help. This anoy me a lot.