Troubles with RDp to Windows server (only 256 colors)

hello

i have a problmem with RDp from iPad2 to MSServer 2003 and MSServer2008

i tried several apps for RDP (from hana mobile, MochaSoft, 2X, ProSoftnet, Thinstuf,...) - and with all apps i have the same problem - even if i chose 16 bit or 24 bit colors - the connection only shows 256 colors at the end - any ideas how i could solve this? ​