How do I increase the desktop heap size on Windows 2008\Vista to more than 64MB?

Hi,

I tried to increase my desktop heap size on Windows 2008 and Vista, but the maximum value I can get is 64MB. I cannot find this restriction to be documented anywhere, so is this the maximum value?

I increased the SharedSection of the Registry value from the default value (20MB for Win2008, 12MB for Vista) to 150MB. - HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\SubSystems\Windows.

However, when I run the testlimit utlility (http://blogs.technet.com/b/markrussinovich/archive/2010/02/24/3315174.aspx) which uses up the desktop heap, it used only 64MB.

And according to http://blogs.msdn.com/b/ntdebugging/archive/2007/07/05/desktop-heap-part-2.aspx , the desktop heap size is no longer limited by the SessionViewSize  on 2008 and Vista, so is 64MB the maximum size of a single desktop heap?

Thank you,
Daniel Pavlic