Crucial 1GB x 2 in my new T60 2623-D6U.

Where are you based?

The US only allows channels 1-11. Whereas Europe allows 1-13. Perhaps installing a European driver/firmware version will enable channels 12 & 13?

Actually, I recall seeing something in the Thinkpad BIOS which says something like 'make hidden pre-desktop area (recovery area) available to Operating System' under configuration? Maybe this is what you need to enable?

I actually tried installing the latest build onto a USB hard disk but the install crashed. I'm wary of installing a beta onto my main drive.
I'll report back if I make any more progress on installing vista... I'm curious to see how it will run.