freebsd stable - Mar 2006 - FreeBSD-6.1-PRERELEASE and PAE

Hello,

I tried 6.0-STABLE/6.1-PRERELEASE on Dell PowerEdge 6800 with PAE option, but
until now no success.

PE6800 has only following input device
      Input Devices  
           USB mouse, USB keyboard, USB KVM dongle
           
            Ports  
                 Rear: two Universal Serial Bus (USB) 2.0, 9-pin serial, video,
ID push button with blue/amber LED
                 
                 Front: Two Universal Serial Bus (USB) 2.0, ID push button with
blue/amber LED, 15-pin video, system power on/off button
                 

            But PAE doesn't work with USB devices.

            How can I to enable memory higher than 4GB on PE6800?

            I tried to install AMD64 FreeBSD-6.0-RELEASE on PE6800, can't
boot.

            Balgaa