ok my post is english too..
Thank you. :)
As far as I have read, 5040x1050, doesn't work on TH2G yet with the 5000 series. ATI has been made aware of the problem here and hopefully it will be fixed.
http://www.widescreengamingforum.com/node/11180
I would like to add that there is a firmware update for TH2G digital edition which offers 5040x1050 on some ati cards. It might be that Matrox needs to update again if the 5000 cards should be supported.
THDE_v2.3.40.t6.56
Jul. 7, 2009 Firmware utility for TH2GO DE
Adds support for 5040x1050 for some ATI GPUs