HD5870 eyefinity 6 with 3 projector 1024*768 problem

[eyescore]

(i post it again the other is delete, i don't know why!)
hello all,
I am a new french user, and hopefully not make a mistake on this forum.
i hope my english is not too unpleasant...

I searched for a solution to my problem for a while but no response has been found

My question:
I have a XFX 5870 Eyefinity 6 (6 DP out )
i work on windows seven.

I want to use 4 video projectors XD600 Mitsubishi (native resolution: 1024 * 768)

These projectors do not have DVI, only HDMI or VGA

but when I use:
4 adapters DP> DVI.
4 cables DVI> HDMI
OR
active adaptor DP> VGA

I can have the 4 projectors independent in 1024 * 768
but when I go into group mode

I have no longer access to the resolution 4096 * 768
Only:
7680 * 1080
5120 * 720
3200 * 800
and some other

Is it a EDID problem ? but VGA don't have edid i think

know where it come from?
I block from the top all day and I turn around you who seem knowledgeable

Thank you very much for your reply
I remain available for any questions about this
Alex

[suiken_2mieu]

The issue is EDID. It's showing that the largest supported resolution is 1920x1080.

There's a tread about getting custom resolutions:
http://www.widescreengamingforum.com/forum/viewtopic.php?f=64&t=17635