Hello,
I would like to ask what I am doing  wrong and what is the best approach to resolve this situation:

First of all I start virtual machine by virDomainCreateXML. In my application I use libvncclient library that sends mouse events to this running domain. I had some troubles with coordinates of mouse cursor but all problem was solved when I added <input type='tablet' bus='usb'/> to xml configuration. 
So now I have a running domain and I want to create snapshot and then after some operations I want to restore this snapshot. I use virDomainSave and virDomainRestore that work fine. The only problem is, that after creating and restoring snapshot I have the same problem with coordinates of mouse. I need  to create and restore snapshot also with <input type='tablet' bus='usb'/> somewhere specified. I also tried methods  virDomainSaveFlags with xml configuration string(see below) as parameter  *dxml, but method fails with: libvir: Domain Config error : XML error: domainsnapshot.Unable to create snapshot.

What should I add to xml configuration? I look at http://libvirt.org/formatsnapshot.html on example but I dont know what paths I should use in my program. I dont understand much snapshots and similar stuff so could you give me example how could I edit my xml configuration? Or what I should do to make virDomainSave and virDomainRestore work?

xml configuration:

<domain type='kvm'>
                <name>Name</name>
                  <uuid>c7a5fdbd-cdaf-9455-926a-d65c16db1810</uuid>
                <memory unit='KiB'>524288</memory>
                  <currentMemory unit='KiB'>524288</currentMemory>
                  <vcpu>2</vcpu>
                  <os>
                   <type arch='x86_64' machine='pc'>hvm</type>
                   <boot dev='hd'/>
                 </os>
                  <devices>
                    <input type='tablet' bus='usb'/>
                    <emulator>/usr/bin/qemu-system-x86_64</emulator>
                    <disk type='file' device='disk'>
                          <source file='/home/lukas/Desktop/Image.img'/>
                          <target dev='hda'/>
                    </disk>
                    <interface type='network'>
                          <source network='default'/>
                    </interface>
                    <graphics type='vnc' port='5901'>
                        <listen type='address' address='127.0.0.1'/>
                    </graphics>
                  </devices>
            </domain>