Z61p + Advanced Mini Dock = screen problem

[Pepa]

Hello,

im having toubles using mine Z61p (ATI Mobility FireGL V5250) with Advanced Mini Dock + external monitor (no matter if its DVI or D-Sub). While i have only mine ThinkPad in dock, everything is working fine. But when i connect some external monitor (and im using both, TP internal display and external one), screen flickers for 1s from time to time - about once per 10 mnutes. Strange is, that flickers randomly both - sometimes internal LCD, sometimes external, sometimes both.

I have tried to change Mini Dock with mine collegue, but without luck (im experiencing same problem on his Mini Dock and his LCD). Mine motherboard was twice changed for some defects and i'm almost sure that problems were the same even with mine previous motherboard...

Anyone has seen problem like this? And has any solution?