HP z800 running Vista loses NVIDIA display settings after Windows Update

Not sure if this is a SuperUser question or not... I'm approaching from the administrator's perspective.

One of my users is on an HP z800 workstation running a financial trading application. This system contains two nVidia adapters powering SIX 24" displays in a 3 x 2 grid. The OS is Vista Business 64-bit SP1 with 24GB RAM and X5570 CPUs. It's a big system.

One of the issues we have with the workstation is that Windows Vista OS updates (now served via WSUS, but previously disabled) cause the NVIDIA displays to lose their placement. Instead of:

[ 1 ] [ 2 ] [ 3 ]
[ 4 ] [ 5 ] [ 6 ]

I get:

[ 1 ] [ 4 ] [ 3 ]
[ 5 ] [ 2 ] [ 6 ]

or:

[ 1 ] [ x ] [ 3 ]
[ 2 ] [ x ] [ x ]

Where "x" is a disabled monitor.

This is an ugly situation because the behavior is a bit unpredictable and I can't figure out how to get the settings to "stick". Is there a trick to this? I'd like things to persist across reboots.

The cards are FX580 and NVS450, with a mix of Display Port and DVI cables connected.