Sony SLT mirror replacement

[Aanything]

Hi,
Some weeks ago I noticed a small dent in my slt-a55's translucent mirror. It must have happened while I was changing lens, adapter or who knows. (I'll eventually post a pic later)
Anyway, so far this is not a problem, since everything seems working fine (even though i do not check AF often), i even tried to remove the mirror and use the camera without that, no problem.

The thing is maybe I'm going to sell that camera and go for a full frame - not sure, not soon, but possibly: so I will have to replace the mirror, and I think I am able to do this by myself - if I find a spare one.

I called sony assistance and they told me that I have to send them my camera to do that: it will cost me some money (don't know how much) and, even worse, i will have to wait without my camera.

So, two questions:
does anybody know where can I get one of those translucent mirrors? maybe one already mounted on its plastic frame, so that i will replace it in 4 seconds?

And does anybody get any clue on how did I hit the mirror (not really important, just for curiosity)

Thanks.

[Orio]

Have you tried calling some independent repair labs?

[Aanything]

I will search for one, maybe in Milan.
Really hope they can help me without having to give them the camera: the replacement is such an easy operation that I'd rather spend no money for it.

Thanks for the idea.