Unfortunatelly, ThinkPad is NOT suported by them directly, meaning that Lenovo must repackage the driver themselves. The latest driver in system update for lenovo is 8.442.3-080103a1-057754C-Lenovo -- clearly an older driver. When will the new drivers become available?
When I was using driverers that were supplied with the laptop originaly, 2 external monitors (through docking station) worked fine, but when I updated to 8.442, a number of visual problems occured: various incorrect image scaling, inability to play videos with VLC (works fine on the laptop screen, but not on the external monitors in the same video mode), and, most significantly - ocasional crashes - the laptop simply freezes with black screen, no messages.
Roll back your driver, you can still download the old driver from Lenovo's support site. Or use the latest Omega Catalyst driver instead, it has less problem been recognised by the laptop as compared to the normal Catalyst driver.