Upgraded to new MBP, lost highest res available on secondary monitor

I've posted this over at the official apple support forums but nothing useful so far. Hoping you guys can help!

Up until yesterday I have been running a Late 2006 15" MacBook Pro with an external monitor. A 19" CRT SyncMaster 997MB Samsung SyncMaster 997MB 19" CRT Monitor ( 997MB ) - 19" CRT Monitor - Samsung Monitor, running at a resolution of 1920x1440 (it did even offer me a crazy res of 2xxx something but I stuck with the 1920). Using an apple DVI to VGA adaptor.

Yesterday I bought a shiny new 2.66 i7 macbook pro (running 10.6.4), and a VGA to Mini Displayport adaptor. However now the max resolution I can set the syncmaster to is 1600x1200 which is a considerably smaller res than what I had before, on an almost 4 year old MBP!

The monitor is perfectly capable of displaying 1920x1440 but my new MBP can't see it! Is there anyway to over ride or set manually the output resolution to the secondary monitor?
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This was my original post.
Since then I have fiddled with DisplayConfigX, 'installed' 1920x1440, which it states the monitor should support. But system is still not showing it after a restart (oddly it does now add a slighty higher res option of 1664x1248).

I plugged my old MBP back in and sure enough, straight to 1920x1440.

Why is my new MBP not giving me this resolution?

Help!!

There was a firmware update released for that adapter. I assume you're using Apple's adapter. Open up software update while the adapter is connected with the external monitor on.

Edit:
There are multiple reports of this adapter maxing out at 1600x1200. Don't know if that firmware update dealt with that or not, but worth a shot.

yes I looked into the firmware, currently 1.03. The only download I can find online is for version 1? So I'm guessing there is no further update.

But as of yesterday I can take it to 1664x1248.