15" wont allow full resolution for external monitor

As title reads. I have an Eizo 22" screen that I have connected to the MBP. I've read all the threads about the same issue, but even when I turn off mirroring I am not given anymore more options to increase the resolution even though I'm more than sure that my Eizo is capable of doing more than 1600 x 1050...

So what's the trick to get full res of the external connected via minidisplay to dvi when mirroring is turned off?

simsaladimbamba said:

This 22" EIZO display has 1680 x 1050 as native resolution: http://www.eizo.com/global/products/flexscan/s2233w/index.html

Just look for your exact model and search for the technical specifications for that model.

Click to expand...

The model I have is closer to this
http://www.eizo.com/global/products/coloredge/cg232w/index.html

Only I have the cg222w

Hm checked myself now... you're right, it just bugs me that I recall using a higher resolution when it was connected to my old windows machine.