When i try create a vm with a serial port in libvirt 0.8.2, the vm don't recognize the serial port, but when i try the same xml with libvirt 0.7.5, the vm recognize correctly the serial port.

the XML is this:
<?xml version="1.0" encoding="UTF-8"?>
<domain type="kvm">
  <name>uml2</name>
  <memory>1048576</memory>
  <vcpu>1</vcpu>
  <os>
    <type arch="i686">hvm</type>
    <boot dev="hd"/>
    <boot dev="cdrom"/>
  </os>
  <features>
    <pae/>
    <acpi/>
    <apic/>
  </features>
  <clock sync="localtime"/>
  <devices>
    <emulator>/usr/bin/kvm</emulator>
    <disk type="file" device="disk">
      <source file="/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/fs/root_cow_fs"/>
      <target dev="hda"/>
    </disk>
    <disk type="file" device="cdrom">
      <source file="/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/fs/opt_fs.iso"/>
      <target dev="hdb"/>
    </disk>
    <interface type="bridge" name="eth1" onboot="yes">
      <source bridge="Net0"/>
      <mac address="fe:fd:00:00:01:01"/>
    </interface>
    <graphics type="vnc" listen=""/>
    <serial type="unix">
      <source mode="bind" path="/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/uml2_socket"/>
      <target port="1"/>
    </serial>
  </devices>
</domain>


kvm line with libvirt 0.8.2
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.12 -cpu qemu32 -enable-kvm -m 1024 -smp 1,sockets=1,cores=1,threads=1 -name uml2 -uuid f1ab8adf-cfe7-1752-0d53-af397ffcf2cd -nodefaults -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/uml2.monitor,server,nowait -mon chardev=monitor,mode=readline -rtc base=utc -boot cd -drive file=/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/fs/root_cow_fs,if=none,id=drive-ide0-0-0,boot=on -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive file=/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/fs/opt_fs.iso,if=none,media=cdrom,id=drive-ide0-0-1,readonly=on -device ide-drive,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1 -device rtl8139,vlan=0,id=net0,mac=fe:fd:00:00:01:01,bus=pci.0,addr=0x4 -net tap,fd=17,vlan=0,name=hostnet0 -chardev socket,id=serial0,path=/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/uml2_socket,server,nowait -device isa-serial,chardev=serial0 -usb -vnc :0 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 

kvm line with libvirt 0.7.5
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.12 -cpu qemu32 -enable-kvm -m 1024 -smp 1 -name uml2 -uuid fc7f24b0-3745-0fc4-632e-ce639c7fe3e9 -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/uml2.monitor,server,nowait -monitor chardev:monitor -boot cd -drive file=/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/fs/root_cow_fs,if=ide,index=0,boot=on -drive file=/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/fs/opt_fs.iso,if=ide,media=cdrom,index=1 -net nic,macaddr=fe:fd:00:00:01:01,vlan=0,name=nic.0 -net tap,fd=17,vlan=0,name=tap.0 -chardev socket,id=serial0,path=/root/.vnx/simulations/tutorial-r1_xp/vms/uml2/uml2_socket,server,nowait -serial chardev:serial0 -parallel none -usb -vnc :0 -vga cirrus