GDI\Rotation problem on ce6?

Hi, all,
I have a problem when doing lcd screen rotation on a pxa270 based platform
using ce 6.
I saw someone has already discussed this issue here, and changed my driver
code according to these discussions. Then, after I set registry
"[HKEY_LOCAL_MACHINE\System\GDI\Rotation" to the angle of 0,90,180,270, the
screen did rotate right after start up.
However, if the "[HKEY_LOCAL_MACHINE\System\GDI\Rotation" set to 90|270,
dynamic rotation from an application doesn't look right afterwards. It looks
like not repainting the last strip as reported by someone else.
Dynamic ratation works fine if the "[HKEY_LOCAL_MACHINE\System\GDI\Rotation"
set to 0|180 when startup.
Any suggestions to solve this? Thanks in advance.

From Paul Wang

http://www.tech-archive.net/Archive/WindowsCE/microsoft.public.windowsce.platbuilder/2009-05/msg00054.html